Question

In a tangent galvanometer, the circular coil is unwound and rewound to have twice the previous radius. As a result of this, the reduction factor $\left(K\right)$ of the tangent galvanometer is:

• A. unaffected
• B. doubled
• C. quadrupled
• D. halved

Answer 1

Answer: (C)

quadrupled

$K=\frac{2r{B}_H}{{\mu }_{o}n}$
$k\propto \frac{r}{n}$

$r\to 2r$

$n\to n/2$ as total length is same

Hence, k becomes 4 times larger