TUNING FORK

QUESTION:

A vibrating tuning fork when held against the surface of a table produces a loud sound.  Give reason.

ANSWER:

A vibrating tuning fork forces the table top to vibrate. As the table top has large surface area, amplitude of vibration increases. 

2020 ICSE CLASS 10 PHYSICS QUESTION PAPER

Superconductors

QUESTION:

What are superconductors?

ANSWER:

The materials whose resistivity is zero at very low temperature is called superconductors. Example: Mercury below 4K.

Work done on satellite.

QUESTION:

A satellite revolves around a planet in a circular orbit. What is the work done by the satellite at any instant?

Answer:

The work done is zero.  As the Centripetal force by the satellite is perpendicular to the displacement of the body.

FUSE WIRE

QUESTION:

Why is it  not advisable to use a piece of copper wire as fuse wire in an electric circuit.?

ANSWER:

Fuse wire should have low melting point and high resistivity but copper has high melting point and low resistivity. 

STONE AND WATER

Question:

Why does a stone lying in the sun get heated up much more than water lying for the same duration of time?

Answer:

The specific heat capacity of  stone is less than the that of  water.