Question

If the number of turns per unit length of a coil of solenoid is doubled, the self-inductance of the solenoid will

• A. remain unchanged
• B. be halved
• C. be doubled
• D. become four times

Answer 1

Answer: (D)

become four times

Answer 2

Self inductance of a solenoid $=\mu_{0}n^{2}Al$ where $n$ is the number of turns per length $\therefore$ Self inductance is directly proportional to $n^{2}$ Self inductance becomes $4$ times when $n$ is doubled