Competitive Exams: Physics MCQs (Practice-Test 18 of 35)

  1. If the linear density of a rod of length 3 m varies as l = 2 + x, then the position of the centre of gravity of the rod is

    1. 7/3 m

    2. 12/3 m

    3. 10/7 m

    4. 9/7 m

  2. The maximum velocity of a simple harmonic motion represented by y = 3 sin (100t + p/6) is given by

    1. 300

    2. 3p/6

    3. 100

    4. p/6

  3. A simple pendulum of length L is set up inside a wagon sliding down a smooth inclined plane of inclination with the horizontal. The period of oscillation recorded by an observer inside will be

    1. 2p (L/g cos q) ½

    2. 2p (L/g sin q) ½

    3. 2p (L/g) ½

    4. 2p (L cos q) =

  4. In an elastic one-dimensional collision between two particles, the relative velocity of approach before collision is

    1. greater than the relative velocity of separation after collision

    2. less than the relative velocity of separation after collision

    3. equal to the relative velocity of separation after collision

    4. less than the relative velocity of separation if the incoming particles heavier than the target particle.

  5. Annihilation of 1 gm of matter could theoretically yield electric energy of the order of

    1. 1032 eV

    2. 1013 eV

    3. 103 eV

    4. l eV

  6. The rest mass of the photon of frequency v is

    1. zero

    2. hv

    3. hv/c2

    4. infinite

  7. In the case of a fluid, Bernoulli's theorem expresses the application of the principle of conservation of

    1. linear momentum

    2. energy

    3. mass

    4. angular momentum

  8. Small droplets of 1iquid assume spherical shape because

    1. energy due to surface tension is lowest for a sphere

    2. energy due to surface tension is the highest for a sphere.

    3. volume energy is the highest for a sphere

    4. surface tension acts against the force of gravity