Question

A new flashlight cell of emf 1.5 volts gives a current of 15 amps, when connected directly to an ammeter of resistance 0.04 ohm . The internal resistance of the cell is

• A. $0.04\Omega$
• B. $0.06\Omega$
• C. $0.10\Omega$
• D. $10\Omega$

Answer 1

The correct option is B $0.06\Omega$

By using $i=\frac{E}{R+r}\Rightarrow 15=\frac{1.5}{0.04+r}\Rightarrow r=0.06\Omega$