Physics MCQs Archives

41. When a force is applied at one end of an elastic wire it produces at strain ∝ in the wire. If y is the youngs modulus of the material of the wire the amount of energy stored per unit volume of the wire is given by

A. Y∝

B. 2Y∝

C. Y∝/2

D. Y∝2

✅ The correct answer is option D.

42. Which one of the following properties of light does not change with the nature of the medium?

A. Velocity

B. Wavelength

C. Amplitude

D. Frequency

✅ The correct answer is option D.

43. A wire suspended vertically from one end is stretched by attaching a weight of 20N to the lower end. The weight stretches the wire by 1mm. How much energy is gained by the wire?

A. 0.01J

B. 0.02J

C. 0.04J

D. 1.0J

✅ The correct answer is option A.

44. Light reaches the earth from the sun in nearly

A. 15 minutes

B. 10 minutes

C. 8 minutes

D. 8 minutes 30 seconds

✅ The correct answer is option D.

45. A certain stress applied to an elastic material produces a certain strain in it. If the elastic limit is not exceeded the energy gained per unit volume of the material is given by

A. Stress/strain

B. (stress/-strain)

C. Stress x strain

D. (Stress/strain)

✅ The correct answer is option D.

46. The photoelectric effect was given by

A. Hertz

B. Fresnel

C. Einstein

D. Plank

✅ The correct answer is option C.

47. Which of the following is the correct statement?

A. No photo electronic emission takes place if the frequency of radiation however intense it may be is less than a certain critical value called threshold frequency

B. Threshold frequency depends upon the nature of the metal surface

C. The maximum energy of a photoelectron is a function of frequency rather than intensity of radiation

D. All of the above

✅ The correct answer is option D.

48. According to Einstein light travels from one place to another in the form of

A. Waves

B. Particles

C. Photons

D. It was not his discovery

✅ The correct answer is option C.

49. Which of the following is NOT the correct statement?

A. A frame of reference which is either at rest or moves with a constant velocity is called an inertial frame of reference

B. An un-accelerated frame of reference is called an inertial frame of reference

C. All the frames of reference in uniform rectilinear motion are equivalent

D. Newtons laws of motion are valid in an accelerated (non-inertial) frame of reference

✅ The correct answer is option D.

50. Longitudinal waves do not exhibit

A. Reflection

B. Refraction

C. Diffraction

D. Polarization

✅ The correct answer is option D.