Physics objective test for Exams

Physics objective test for Exams
Physics Objective Questions And Answers Free
Physics - Online Multiple Choice

1. In a germanium semiconductor material used in transistors, mobility of electrons is 3900 cm2/V How much velocity do they have?
(a) 3900 m/s
(b) 7800 m/s
(c) 1000 m/s
(d) 4000 m/s
Ans. (a)

2. Curie temperature of. Iron is that temperature below which it is : -
(a) Ferromagnetic
(b) Electrically conducting
(c) Superconducting
(d) Radioactive
Ans. (a)


3. In radio reception, the strength of the received signal varies and to provide a constant output power, it is necessary to vary the gain power, it is necessary to vary the gain of the receiver. This is usually done by:
(a) a diode
(b) a pentode
(c) n-p-n transistor
(d) Automatic volume control
Ans. (b)

4. An electric charge is surrounded by several other electric charges. The force exerted by one of the surrounding charges on this charge:
(a) Decreases because of the other charges
(b) Increases because of the surrounding charges
(c) Is independent of the presence of other charges
(d) Depends on the position of other charges
Ans. (c)

5. Which one of the following pairs is NOT correctly matched?
(a) Pion — Meson
(b) Proton — Baryon
(c) Neutrins — Lepton
(d) Lambda — Meson
Ans. (d)

6. Which of the following factors do not affect the frequency stability of an oscillator?
(a) Output load
(b) Inter-element capacitances and stray capacitances
(c) Temperature variation
(d) Coil size
Ans. (a)

7. Which one of the following is a set of magic numbers?
(a) 1, 2, 8, 16, 20, 28
(b) 2, 8, 16, 20, 28, 50
(c) 8, 28, 50, 82, 100, 126
(d) 2, 8, 20, 28, 50, 82, 126
Ans. (d)

8. Carbon dioxide shows a Raman line at 1080 cm-1. Consider the, following statements in this regard:
1. The corresponding infrared absorption will be found at 1080 cm-1.
2. The corresponding infrared absorption band will be absent.
3. CO2 is a linear and symmetric molecule.
Of these statements:
(a) 1 and 3 are correct
(b) 2 and 3 are correct
(c) 2 alone is correct
(d) 3 alone is correct
Ans. (a)

9. The average binding energy per nucleon is 7.6 MeV for a heavy nucleus such as uranium while it is 8.5 MeV for nuclei with mass numbers around 110. The energy released. in binary fission of U—235 by slow neutrons will be approximately:
(a) 7.6 MeV
(b) 8.5 MeV
(c) 212.4 MeV
(d) 235 MeV
Ans. (c)

10. In a prism, the dispersion is related to the wavelength λ as
(a) λ-1
(b) λ-2
(c) λ-3
(d) λ-4
Ans. (c)

11. A light ray travels through media A and B having refractive indices of 4/3 and 3/2 respectively. If the thickness of the medium A is 4 cm and that of B is 6 cm, then the optical path length in the combined media will be:
(a) 7/3
(b) 12/3
(c) 37/3
(d) 43/3
Ans. (d)

12. When excited by a light of wavelength 4358 Å, a transparent substance produces a Stokes Raman frequency shift of 458 cm-1. The wavelength of the antistokes line is:
(a) 4058 Å
(b) 4274 Å
(c) 4448 Å
(d) 4548 Å
Ans. (b)

13. An ultrasonic sound pulse is sent vertically down the ocean waters and the echo is received 3 s later. The depth of the ocean at that place is approximately:
(a) 1.1 kin
(b) 2.2 km
(c) 3.3 km
(d) 4.4 km
Ans. (b)


14. When two tuning forks A and B are sounded together 6 beats/s are produced. The frequency of B is 320 Hz. If some wax is added to A and again sounded with B, again 6 beats/s are produced. The frequency of A is:
(a) 326 Hz
(b) 332 Hz
(c) 314 Hz
(d) 308 Hz
Ans. (a)

15. Two railway engines removing on parallel tracks in opposite direction, each with a speed of 72 km/h. The whistle of one engine blows a note of frequency 589 Hz. Given that the velocity of sound is 330 m/s, the frequency which will be heard by the driver of the other engine, just before crossing is
(a) 919 Hz
(b) 665 Hz
(c) 589 Hz
(d) 259 Hz
Ans. (b)

16. A thermos bottle containing coffee is vigorously shaken. If the coffee is considered as a system, then the temperature of the coffee will
(a) Increase slightly
(b) Fall
(c) Remain the same
(d) Never be determined
Ans. (a)

17. An open organ pipe has a fundamental frequency of 300 Hz. The first overtone of this organ pipe is the same as the first overtone of a closed organ pipe. The length of the closed organ pipe is (assume velocity of sound in air as330m/s):
(a) 0.41m
(b) 0.78m
(c) 0.82m
(d) 0.90m
Ans. (a)

18. Steam at 100°C causes more severe burns than water at the same temperature
Because
(a) Steam is a gas
(b) Steam cannot do work
(c) Steam can provide more heat
(d) Steam is highly combustible
Ans. (c)

19. A container having some gas was kept in a moving train. The temperature of the
gas in the container will
(a) Increase slightly
(b) Decrease
(c) Remain the same
(d) Become infinite
Ans. (a)

20. Two glass tumblers have been stuck together (one into the other). They can be
Separated by
(a) placing hot water in the inner tumbler
(b) placing the tumblers in cold water
(c) placing the outer tumbler in hot water
(d) hammering them vigorously
Ans. (c)

21. A test tube containing some water is surrounded by melting ice (pure). Then,
the water in the test tube will
(a) not freeze into ice
(b) freeze into ice
(c) boil ultimately
(d) become steam ultimately
Ans. (a)

22. Heat flows as a result of difference
(a) temperature
(b) weight
(c) mass
(d) none of these
Ans. (a)

23. The quantity of heat required to raise the temperature of 2000 g of water from
10°C to 50°C is
(a) 80 cal
(b) 30,000 cal
(c) 8000 cal
(d) none of these
Ans. (b)

24. The unit of thermal capacity is
(a) cal/°C
(b) cal/g
(c) cal/g/°C
(d) none of these
Ans. (a)


25. If the thermal capacity of a body is infinity, then
(a) Heat can never be added to it
(b) Heat can never be extracted from it
(c) The temperature of the body cannot be altered by adding or extracting any
amount of heat
(d) It has infinite amount of heat
Ans. (c)

Objective physics Questions for UPSC

Objective physics Questions for UPSC
UPSC Exam material Physics objective questions and answers
Free online Physics practice tests: Solved UPSC Physics Question
1. The flowing water of a river possesses energy.
(a) Gravitational
(b) Potential
(c) Electrical
(d) infinite
Ans. (d)
2. The R.D. of a metal b1ock is 2.7 x 103 kg/m3.It is immersed in water. State the situation.
(a) Sinks
(b) Floats
(c) Partially immersed
(d) No part immersed
Ans. (a)
3. The mass of an object P is double the mass of Q. If both move with the same
Velocity, then the ratio of K.E. of P to Q is
(a) 1:2
(b) 2:1
(c) 1:4
(d) 4:1
Ans. (b)
4. Pressure cannot be measured in
(a) Nm2
(b) Bar
(c) Pa
(d) kg wt
Ans. (d)
5. What is the momentum of a body of mass 100 g, having a K.E. of 20 J’?
(a) 2 kg ms-1
(b) 1/2kg ms-1
(c) 2 g cm s-1
(d) none of these
Ans. (a)
6. Pascal is the unit for
(a) Pressure
(b) Thrust
(c) Buoyant force
(d) None of these
Ans. (a)
7. 1 milibar is equal to
(a) 100 N m-2
(b) 100 N m-2
(c) 1 N m-2
(d) 1/100 N m2
Ans. (a)
8. A bird flying in the sky has
(a) K.E. only
(b) P.E. only
(c) Neither K.E. nor P.E.
(d) Both K.E. and P.E.
Ans. (d)
9. The mercury barometer was invented by
(a) Ce1sius
(b) Fahrenheit
(c) Torricelli
(d) Bernoulli
Ans. (c)
10. The atmospheric pressure at the surface of the earth is about
(a) 103 N m-2
(b) 105 N m-2
(c) 10-3 N m-2
(d) 10-5 N m-2
Ans. (b)
11. A total of 4900 joule was expended in lifting a 50 kg mass. The mass was raised
to a height of
(a) 98 m
(b) 960 m
(c) 245 m
(d) 10 m
Ans. (d)
12. The ratio of SI units to CGS units of density is
(a) 103
(c) 102
(b) 10-2
(d) 10-3
Ans. (d)
13. An object of mass 1 kg has a P.E. of 1 J relative to the ground when it is at a
Height of
(a) 0.102m
(b) 1 m
(c) 9.8m
(d) 32m
Ans. (a)
14. The density of water is
(a) 10 kg m-3
(b) 100-2 kg m-3
(c) 102 kg m-3
(d) 103 kg m-3
Ans. (d)
15. Water evaporates under atmospheric pressure. Without changing the temperature,
the same water is placed under partial vacuum. The rate of evaporation will
(a) Increase
(b) Drop to zero
(c) Decrease
(d) Remain unaffected
Ans. (a)
16. The SI unit for the coefficient of linear expansion is
(a) °C
(b) per°C
(c) cm2°C
(d) none of these
Ans. (c)

17. The SI unit for the coefficient of linear expansion is
(a) °C
(b) per°C
(c) cm2/°C
(d) none of these
Ans. (d)
18. A block of wood is floating on water at 0°C, with a certain volume V above
water level. The temperature of water is slowly raised from 0°C. How will
the volume V change with the rise of temperature?
(a) V will be unchanged
(b) V will decrease from 0°C
(c) V will decrease till 4°C and then increase
(d) V will increase till 4°C and then decrease
Ans. (d)
19. Coefficient of linear expansion always_________ with the increase in temperature.
(a) Increases
(b) Decreases
(c) Remains the same
(d) Doubles itself
Ans. (d)
20. Any solid will sink in water if its relative density is
(a) less than unity
(b) Equal to unity
(c) Greater than unity
(d) infinite
Ans. (c)
21. Choose the correct statement:
(a) α: β: γ:: 1:3:2
(b) α: β: γ:: 3:2:1
(c) α: β: γ:: 2:3:l
(d) α: β: γ:: 1:2:3
Ans. (d)
22. Any solid will not sink in water if its relative density is
(a) Less than 1
(b) Equal to 1
(c) Greater than 1
(d) infinite
Ans. (a)
23. A graph is plotted taking °C along the Y-axis and °F along the X-axis.
It is a/an
(a) parabola
(b) Straight line
(c) Ellipse
(d) Circle
Ans. (b)
24. Therm is the unit of
(a) heat
(b) temperature
(c) thermometry
(d) work
Ans. (a)
25. Absolute zero corresponds to
(a) -273 K
(b) 273°C
(c) 273°R
(d) none of these
Ans. (d)

Physics For UPSC IAS

Physics For UPSC IAS
physics for IAS exam Practice on physics MCQ
Physics practice test UPSC IAS

1. The binary number 110000111101 corresponds to a hexadecimal number:
(a) CFD
(b) D3C
(c) DBF
(d) C3D
Ans. (d)

2. A gate with only one input and one output is:
(a) AN OR gate
(b) A NOT gate
(c) A NAND gate
(d) AN AND gate
Ans. (b)

3. Which one of the following statements is not true in case of Zener diode?
(a) There is no similarity between the forward characteristic curves of a diode and Zener diode
(b)A Zener diode has sharp breakdown-voltage
(c) A Zener diode is always reverse-biased
(d) The Zener diode is a heavily doped diode
Ans. (a)

4. A nibble is equal to:
(a) 4 bits
(b) 8 bits
(c) 2 bits
(d) 16 bits
Ans. (a)

5. For a diatomic gas having 3 translational and 2 rotational degrees of freedom, the energy is given by:
(a) 5/2kT
(b) 3/2kT
(c) 1/2kT
(d) kT
Ans. (a)

6. From van der Waals’ equation, one n deduce that the critical temperature Tc of a substance is proportional to:
(a) a /b
(b) b/a
(c) a/b2
(d) b/a2
Ans. (a)

7. Stefan’s law states that the radiation emitted by a black body is proportional to the:
(a) Average kinetic energy of a molecule
(b) Frequency cut-off in the Debye model
(c) Fourth power of the temperature in degree Celsius (To C)4
(d) Fourth power of the temperature in degree Kelvin (TK)4
Ans. (d)

8. The maximum value of the emissive power of a black body corresponds to a frequency v1 at T1K and v2 at T2K. It follows from Planck’s law of radiation that:
(a) T1/T2 = v1/v2
(b) T2/T1 = v1/v2
(c) T12/T22 = v1/v2
(d) T22/T12 = v1/v2
Ans. (a)

9. Which one of the following pairs is correctly matched?
(a) Diamagnetism………. .susceptibility is positive
(b) Paramagnetism……… susceptibility decreases with increasing temperature
(c) Ferromagnetism……... susceptibility is zero
(d) Anti-ferromagnetism…. susceptibility is infinite
Ans. (b)

10. Curie temperature of. Iron is that temperature below which it is : -
(a) Ferromagnetic
(b) Electrically conducting
(c) Superconducting
(d) Radioactive
Ans. (a)

11. An electric charge is surrounded by several other electric charges. The force exerted by one of the surrounding charges on this charge:
(a) Decreases because of the other charges
(b) Increases because of the surrounding charges
(c) Is independent of the presence of other charges
(d) Depends on the position of other charges
Ans. (c)

12. Two large parallel plates, separated by a distance of 3.0 mm have a capacitance of 10 pF and are charged to a potential of 12 V by a battery. The plates are disconnected from the battery and pulled apart to 5.0 mm. The potential difference between the plates is:
(a) 12V
(b) 20V
(c) Zero
(d) 7.2V
Ans. (b)

13. A circular wire loop of radius r is placed in a region of magnetic field B such that the plane of the loop makes an angle θ with the direction of B. Consider the following conditions in this regard:
1. Change in B with time
2. Change in r with time
3. B being non-uniform in space
4. Change in θ with time
The conditions for an induced emf in the loop would
Include:
(a) 1 and 4
(b) 1, 2 and 4
(c) 1 and 3
(d) 2, 3 and 4
Ans. (15)

14. A straight conductor of length 05 m is moved with a speed of 8 m/s perpendicular to a magnetic field of intensity .1.2 Wb/m2. The induced emf across the conductor is
(a) 2.4V
(b) 4.8V
(c) 9.6V
(d) 24V
Ans. (b)

15. The coefficient of mutual inductance of two coils is 0.5 H. If the current is increased from 2 A to 3 A in 0.01 sin the primary coil, then the induced emf in the secondary coil will be
(a) 100V
(b) 75V
(c) 50V
(d) 25 V
Ans. (c)

16. A direct current of 5 A is superimposed on an alternating current I 10 sin cot flowing through a wire. The effective value of the resulting current will be:
(a) 15/2 A
(b) 5√3A
(c) 5J√5A
(d) 15A
Ans. (b)

17. A coil of inductance 5.0 mH and negligible resistance is connected to an oscillator giving an output voltage of
e = l0sin (l00t)
The peak current in the circuit will be:.
(a) 2A
(b) 5A
(c) 10A
(d) 20A
Ans. (d)

18. An electromagnetic wave is propagating in a medium. The quantity √μ/e is the:
(a) Intrinsic impedance of the medium
(b) Square of the refractive index of the medium
(c) Refractive index of the medium
(d) Energy density
Ans. (a)

19. Sign of the Hall coefficient determines the:
(a) Nature of the charge carriers
(b) Magnitude of charge on the carriers
(c) Number density of carriers
(d) Average energy of charge carriers
Ans. (a)



20. If a cyclotron is used to accelerate-electrons, they can attain kinetic energies of the order of a few:
(a) TeV
(b) BeV
(c) MeV
(d) keV
Ans. (c)

physics objective questions and answers

physics objective questions and answers
Physics : Multiple-Choice Questions

Direction: In the following questions more than one of the answers given may be correct. Select the correct answer and mark it according to the code.

Code:

(a) 1 and 2 are correct

(b) 2 and 3 are correct

(c) 1 and 4 and correct

(4)1, 2 and 4 are correct

1. In the case of projectile motion of two projectiles, A and B are projected with the same speed at angles 15° and 75° respectively to the horizontal, then:

(l) H_A<H_B

(2) H_A > H_B

(3) T_A > T_B

(4) T_A < T_B

Ans. (c)

 2. A block is suspended by an ideal spring of force constant k. If the block is pulled down by applying a constant force F and if maximum displacement of block from its initial position of rest is δ then:

(l) F/k < δ < 2F/k

(2) δ = 2F/k

(3) Work done by the force is equal to F δ

(4) Increases in energy stored in spring is ½ k δ²

Ans. (b)

3. The magnitudes of the gravitational field at distance r₁ and r₂ from the centre of a uniform sphere of radius R and mass M are F1 and F2 respectively. Then:     

(1) F1/F2 = r_1/ r₂ if r₁ <R and r₂ < R

(2) F1/F2 = r₂²_/ r₁² if r₁ >R and r₂ > R

(3) F1/F2 = r_1/ r₂ if r₁ >R and r₂ > R

(4) F1/F2 = r₁²_/ r₂² if r₁ <R and r₂ < R

Ans. (a)

4. Function x = A sin² ωt + B cos² ωt + C sin ωt cos cot represents SHM:

(1) For any value of 4, B and C (except C = 0)

(2) If A = -B, C = 2B, amplitude =|B√2|

(3) If A=B, C =2B, amplitude =|B|

(4) If A = B, C = 0

Ans. (b)

5. A wave disturbance in a medium is described by y(x, t) = 0.02 cos (50Πt +Π /2 )cos (10Πx), where x and y are in metre and t is in second?

(1) A node occurs at x = 0.15m

(2) An antinode occurs at x = 0.3 m

(3) The speed of wave is 15 ms

(4) The wavelength is 0.2 m

Ans. (d)

6. A bimetallic strip is formed act of two identical strips one of copper and the other of brass. The coefficients of linear expansion of the two metals are α_c, and α_β. On heating, the temperature of the strip goes up by ΔT and the strip bends to form an arc of radius of curvature R. Then R is:

(1) Inversely proportional to ΔT

(2) Proportional to |α_{c -} α_β |

(3) Proportional to ΔT

(4) Inversely proportional to| α_{c -} α_β |

Ans. (c)

7. For an ideal gas:

(1) The change in internal energy in a constant pressure process from temperature T1 and T2 is equal to nC_v (T — T1), where C_v is the molar heat capacity at constant volume and n the number of moles of the gas

(2) The change in internal energy of the gas and work done by the gas are equal in magnitude in an adiabatic process

(3) The internal energy increases in an isothermal process

(4) No heat is added or removed in an adiabatic process

Ans. (d)

8. A body of mass M is attached to the lower end of a metal wire, whose upper end is fixed. The elongation of the wire is l.

(1) Loss in gravitational potential energy of M is Mgl

(2) The elastic potential energy stored in the wire is 1/2 Mgl

(3) The elastic potential energy stored in the wire is Mgl

(4) Heat produced is Mgl

Ans. (d)

9. When a metal plate is introduced between the two plates of a charged capacitor and insulated from them, then:

(1) The metal plate divides the capacitor into two capacitors connected in parallel to each other

(2) The metal plate divides the capacitors into two capacitors connected in series with each other

(3) The metal plate is equivalent to a dielectric of infinite dielectric constant

(4) The metal plate is equivalent to a dielectric of zero dielectric constant

Ans. (b)

10. A parallel plate air capacitor is connected to a battery The quantities charge, voltage, electric field and energy associated with the capacitor are given by Q0, V0, E0 and U0 respectively. A dielectric slab is now introduced to fill the space between the plates with the battery 1still in connection. The corresponding quantities now given by Q, V, E and U related to the previous one as:

(1) Q>Q₀

(2) V>V₀

(3) E>E₀

(4) U>V₀

Ans. (c)

11. Two identical double convex lenses each of the focal length ƒ is made of glass of μ== 1.5. If R is the radius of curvature of each of the four faces. Then:

(1) The focal length of combination is half the radius of curvature of any of the four faces

(2) The focal length of combination increases if the lenses are separated by a distance f and the new focal length is twice its focal length when the lenses are in contact

(3) The focal length of combination decreases when the lenses are separated by a distance ƒ and the new focal length is half its focal length when the lenses are in contact

(4) None of the above

Ans. (a)

12. Two resistors when connected in series have an equivalent resistance of 9 Ω and when connected in parallel have an equivalent resistance of 2 Ω. The value of these resistance of are

(1) 2Ω and 9Ω

(2) 3Ωand 6Ω

(3) 6Ω and 3Ω

(4) 3Ω and 9Ω

Ans. (b)

13. CapacitorC₁ of capacitance 1μF and capacitorC₂ of capacitance 2μF are separately charged fully by a common battery. The two capacitors are then separately allowed to discharge through equal resistors at time t = 0.

(1) The currents in the two discharging circuits at t=0 are equal but not zero

(2) The current in each of the two discharging circuits is zero at t = 0

(3) The current in the two discharging circuits at t = 0 are unequal

(4) Capacitor C₁, losses 50% of its initial charge sooner than C₂ losses 50% of its initial charge

Ans. (c)

14. When photons of energy 4.25 eV strike the surface of a metal A, the ejected photoelectrons have maximum kinetic energy. T_A expressed in eV and the de-Broglie wavelength λ_A . The maximum kinetic energy of photoelectrons liberated from another metal B by photons of energy 4.70 eV is T_B = ( T_B —1.5 eV). If the de-Broglie wavelength of these photoelectrons IS λ_B = λ_A then:

(1) The work function of A is 2.25 eV

(2) The work function of B is 4.20 eV

(3) T = 2.7 eV

(4) TA= 2.00eV

Ans. (d)

15. Let λ_α, λ_β and λ_α’  a denote the wavelength of the X-rays of the K_α, K_β and L_α lines in the characteristics, X-rays for a metal:

(1) λ_α  > λ_β >  λ_α ‘

(2) λ_α  > λ_α’  > λ_β

(3) λ_β  = 1/ λ_α + 1/ λ_α’

(4) 1/λ_α + 1/ λ_β = 1/ λ_α’

Ans. (b)