ICSE ICSE Class 7 - CISCE Question Bank Solutions

The diagram in Fig. shows an incident ray AO and the reflected ray OB from a plane mirror. The angle AOB is 30°. Draw normal on the plane mirror at the point O and find:

The diagram in fig. shows an incident ray AO and the normal ON on a plane mirror. Draw the reflected ray. State the law you use to draw the direction of the reflected ray.

Write true or false for a given statement.

Sound can travel in a vacuum.

Fill in the blank.

Sound travels faster in ________ than in liquids.

Select the correct alternative : 

The speed of sound in water is

Describe an experiment to show that sound can travel in water.

Describe an experiment to show that sound can travel in a solid.

Write the approximate speed of sound in air.

Write the approximate speed of sound in water . 

Write the approximate speed of sound in steel.

During a thunderstorm, the sound of a thunder is heard after the lightning is seen. Why?

Can sound travel through solids and liquids ? In which of these two does it travel faster ?

A boy fires a gun and another boy at a distance of 1020 m hears the sound of firing the gun 3 s after seeing its smoke. Find the speed of sound.

A boy on a hill A fires a gun. The other boy on hill B hears the sound after 4 s. If the speed of sound is 330 m s-1, find the distance between the two hills.

Write true or false for a given statement.

In an electromagnet, the core is made up of copper.

Write true or false for a given statement.

An electric bell uses an electromagnet.

Write true or false for a given statement.

An electromagnet with soft iron core is a temporary magnet.

Fill in the blank

 An electromagnet is used to separate large mass of ______ scrap.

Fill in the blank

The strength of the magnetic field of an electromagnet is increased by inserting a core of soft ______

Select the correct alternative

Electromagnets are made up of