Question

The electric field intensity produced by the radiations coming from a 100 W bulb at a 3 m distance is E. The electric field intensity produced by the radiations coming from 50 W bulb at the same distance is

Answer 1

answer

Power of bulb=100W

Intensity of Electric field at a distance 3m is E.

The electric field intensity is given by:

E=

A

P

⇒E=

πr

2

100

=

π×3

2

100

=

9π

100

watt/m

2

Similarly, E at a distance of 3m produced by 50W bulb is:

⇒E

1

=

πr

2

50

watt/m

2

=

9π

50

watt/m

2

E

1

E

=

9π

100

÷

9π

50

⇒

E

1

E

=

9π

100

×

50

9π

=2

⇒E

1

=

2

E