Why do magnetic axis

.we take one-fourth of the time period of the bar as the time of fall?

Because the bo

the bob travels the vertical distance in the same time as the bar completes one-fourth of

Is 0SCillation.

ftwo

o unequal masses are dropped from the same height, they will reach the surface of the

urth in the same time. Why?

Recause both of these poSSess the same value of acceleration due to gravity (g).

omes four times?

Im.

suspension.

ive motion between

will'g change if length of a pendulum is changed?

on and minimum at

No. The value of g 1S constant at a place.

Will g change if the pendulum is taken to the top of a high mountain or into a deep cave?

Yes. The value of 'g' decreases both with the height or depth from the surface of the earth.

: Does the value of 'g decrease at he same rate for distances above the earth than for the

same distances below the earth?

No. the value of 'g decreases at a faster rate for distances above the earth's surface than for the

same distances below the surface of the earth.

f we go up a distances 2R( where Re is the radius of the earth). Then 'g' decreases to what

value?

GMe

It decreases to g/9; because g =p2and in this case R = 3Re

Experiment No. 6B ( Digital Free Fall)

What is a magnet?

A magnet is an iron ore which can attract small pieces of iron, cobalt, nickel and steel. This is

S.

called "attractive property. When it is freely suspended, it points in the north-south direction.

This is called "directive property. A magnet always has two poles. (North pole and South pole).

Its like poles repel but unlike poles atiract each other.

ction of grav-

Define magnetic pole and magnetic field.

The poles of a magnet are the regions in a magnet where the magnetic attraction is the greatest.

The line passing through the two poles is called "magnetic axis."

Magnetic field is the region around a magnet in which it can attract or repel objects by inducing

magnetism.

of the earth

What are permanent magnetsS

The magnets which can retain their magnetism for a long time are called permanent magnets.

Natural magnet (or lodestone -magnetic oxide ot iron) is an example. Steel and alloys of cobalt,

nickel and aluminium (e.g. Alcomax. Alnico, Iiconal, etc.) are used for producing powerful

permanent magnets. They are used in mariner S compass, in computer memory unit and in vari-

Ous electric meters.

What are temporary niagnets