Question

5.A circuit may have(a) only one bulb(c) only three bulbs(b) only two bulbs.(d) any number of bulb​

Answer 1

Explanation:

Correct option is

C

Bulb B would get brighter and bulb C would get dimmer

When bulb didnot burn out, Bulb A is wired in parallel with bulb B and this combination is wired in series with bulb C with equal resistance r.

Effective resistance will be

r+r

r×r

+r=

2

3r

.

Current through C is

2

3r

v

=

3r

2v

where v is voltage.

Current through A and B is

2×3r

2v

=

3r

v

When bulb A burns there are only two bulbs in series connection and the effective resistance become 2r with the current flowing though B and C being Case 1 :

2r

v

.

Now brightness depends on the power which in turn is proportional to current.

Current in B increased to

2r

v

from

3r

v

and in C decreased to

2r

v

from

3r

2v

.

So Bulb B would get brighter and bulb C would get dimmer.

Answer 2

Answer:

A circuit may have any number of bulbs

Explanation:

A circuit may have any number of bulbs. They may be dimmer or brighter than each other according to the number of bulbs but 4 or 5 or any number of bulbs can be their.