Question

Ram has an LED of resistance 10 Ω which will only light up if the current provided is exactly 1A. He also has 10 two volt cells. Find out how many cells will Ram need to light up the LED?

• A. 2
• B. 10
• C. 5
• D. 1

Answer 1

The correct option is C

5

Given, R = 10 Ω , I = 1 A

Required voltage,$V=I\times R=10V$

Since each battery can supply 2 V, we require 5 such batteries to light up the LED.