Force and Laws of Motion — Science STD 9 — Question

The ratio of the radii of the atom to the nucleus is:

The National Dairy Development Board (NDDB) designed and implemented the world’s largest dairy development programme, called “Operation Flood”, which came out to be the reason behind White Revolution in India. Can you name the man who is known as the Father of White Revolution?

Give reason as to why relative density has no unit:

The property/ properties which enable copper metal to be used for making electric wires is/ are:

1. Copper metal is malleable and ductile.
2. Copper metal is a good conductor of electricity.
3. Copper metal is ductile and has low electrical resistance.
4. Copper metal is sonorous and an excellent conductor of electricity.

The nucleus is the site for synthesis of:

Which of the following situations involves the Newton's second law of motion?

1. A force can stop a lighter vehicle as well as a heavier vehicle which are moving.
2. A force can accelerate a lighter vehicle more easily than a heavier vehicle which are moving.
3. A force exerted by a lighter vehicle on collision with a heavier vehicle results in both the vehicles cor to a standstill.
4. A force exerted by the escaping air from a balloon in the downward direction makes the balloon to go upwards.

When water at 0°C freezes to form ice at the same temperature of 0°C, then it:

1. Absorbs some heat.
2. Releases some heat.
3. Neither absorbs nor releases heat.
4. Absorbs exactly 3.34 × 10⁵J/ kg of heat.

On listening to his friend, Amit said “Moon does not work as it goes round our earth”, because:
A: Moon displaces perpendicular to direction of force.
B: No force acts on the moon.
C: Momentum change is non-zero.
Which of the combination is/ are correct?

Suppose a boy is enjoying a ride on a merry-go-round which is moving with a constant speed of 10ms^-1. It implies that the boy is: