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Physics · PYQ NEET UG 2022
हिन्दीA long solenoid of radius \( 1\text{ mm} \) has \( 100 \) turns per \( \text{mm} \). If \( 1\text{ A} \) current flows in the solenoid, the magnetic field strength at the centre of the solenoid is:
Correct answer · Option 4
\( 12.56 \times 10^{-2}\text{ T} \)
Explanation
Magnetic field \( B = \mu_0 n I \), where \( n = \frac{100}{10^{-3}\text{ m}} = 10^5\text{ turns/m} \). Thus \( B = 4\pi \times 10^{-7} \times 10^5 \times 1 = 4\pi \times 10^{-2} = 12.56 \times 10^{-2}\text{ T} \).
