Question

By using only two resistance coils-singly, in series, or in Parallel-one should be able to obtain resistances of $3, 4, 12$ and $16$ ohms. The separate resistances of the coil are

• A. 3 and 4
• B. 4 and 12
• C. 12 and 16
• D. 16 and 3

Answer 1

Answer: (B)

4 and 12

Answer 2

If we take $R_{1}=4 \Omega, R_{2}=12 \,\Omega$, then in series
resistance $R=R_{1}+R_{2}=4+12=16 \Omega$
In parallel, resistance $R=\frac{4 \times 12}{4+12}=3 \Omega$
So , $R_{1}=4 \Omega$ and $R_{2}=12 \,\Omega$