When a wave enters from one medium to another, which property is not affected ?

• Amplitude

• Wavelength

• Speed

• Frequency

The amount of work is maximum when the angle between the direction of the force and displacement is _______ $\degree$ ?

• 90

• 45

• 180

• 0

If velocity is doubled then ...

• Momentum and K.E. remain same

• Momentum increases by 4 times and K.E. by 2 times

• Momentum increases by 2 times and K.E. by 4 times

• Momentum increases by 2 times and K.E. by 2 times

A gas filled balloon possesses what ?

• Kinetic Energy

• Potential Energy

• Just Energy

• None of the above

If a force applied to an object is parallel to the ground, and the object moves perpendicular to the ground, the work done will be _______________ .

• Positive

• Zero

• Negative

• Maximum

The time period of a simple pendulum depends upon ________ ?

• Temperature

• Length

• Mass of the bob

• Amplitude

Which physical quantity is related to the loudness of sound ?

• Timbre

• Amplitude

• Frequency

• Wavelength

In 15 days the activity of a sample of radioactive bismuth decreases to 1/8 of it's original activity. Calculate it's half life.

• 9

• 5

• 3

• 8

Imagine a man weighs his weight in an elevator accelerating downwards with a magnitude equal to the gravitational acceleration. What value will the weighing scale display ?

• The scale will be unable to give a steady reading

• The mass of the person x gravitational acceleration

• 9.81

• 0

2 parallel forces of 500.8 N and 312.4 N act on an object in opposite directions. If it's mass is 50 g, what's the magnitude of the acceleration of the object ?

• $3768\ ms^{-2}$

• $1400ms^{-2}$

• $9420ms^{-2}$

• $1626ms^{-2}$