A light bulb used in a slide projector draws a current of 6 amperes when operating on 120 volts.
-If two slide projectors are connected in series across the same 120-volt source,the current drawn from the source in amperes is
A)3.
B)6.
C)9.
D)12.
E)none of the above.

Question

Quizplus · Accepted Answer

When two slide projectors are connected in series, the effective voltage across each projector is only half of the total voltage i.e. 120/2 = 60 volts.

The resistance of the bulb remains the same, and we know that V = IR. 
If V decreases, then current I must also decrease to maintain the same resistance.

Thus, each projector will draw a current of 6A/2 = 3A.

Therefore, the total current drawn from the source is 3A + 3A = 6A.

Hence, the correct option is A) 3.

A Light Bulb Used in a Slide Projector Draws a Current