Question

The internal resistance of a cell of e.m.f. $2$ volts is $0.1 \Omega$. It is connected to a resistance of $3.9$ $\Omega$. The voltage across the cell will be (in volts)

• A. $1.95 \,V$
• B. $0.5\, V$
• C. $2\, V$
• D. $1.9\, V$

Answer 1

Answer: (A)

$1.95 \,V$

Answer 2

Given: Internal resistance of the ccll $(r)=$ $0.1 \Omega ;$ E.M.F. of the cell $(E)=2 V$ and cxtcmal rcsistance $(R)=3.9 \Omega$. We know that voltagc $(h)=E-l r$ $=E-\frac{E}{R+r} \cdot r=2-\frac{2}{3 \cdot 9+0 \cdot 1} \times 0 \cdot 1=1.95 \,V$