Question 1 of 3 The magnetic field intensity at the center of a circular coil of radius R and carrying current I is A [latex]\dfrac{\mu_o I}{R}[/latex] B [latex]\dfrac{\mu_o I}{2R}[/latex] C [latex]\dfrac{\mu_o I}{2\pi R}[/latex] D [latex]\dfrac{2\mu_o I}{R}[/latex] 💡 Explanation The magnetic field at the center of a circular coil of radius [latex]R[/latex] carrying current [latex]I[/latex] is [latex]B = \dfrac{\mu_o I}{2R}[/latex], derived directly from the Biot-Savart law. Question 2 of 3 A charge of 2 Coulomb is moving with velocity of 0.5 [latex]ms^{-1}[/latex] at an angle of 30° in a magnetic field of 4T. What will be the magnetic force experienced by the charge? A 1N B 2N C 4N D 0.5N 💡 Explanation Using [latex]F = qvB\sin\theta = 2 \times 0.5 \times 4 \times \sin 30^\circ = 4 \times 0.5 = 2N[/latex]. Question 3 of 3 Current sensitivity of a moving coil galvanometer is 5 div/mA and its voltage sensitivity is 20 div/V. The resistance of the galvanometer is A 40Ω B 25Ω C 250Ω D 500Ω 💡 Explanation Galvanometer resistance is given by [latex]G = \dfrac{\text{Current sensitivity}}{\text{Voltage sensitivity}} = \dfrac{5\ \text{div/mA}}{20\ \text{div/V}} = \dfrac{5 \times 1000\ \text{div/A}}{20\ \text{div/V}} = 250\ \Omega[/latex]. ← Prev Check Next → Finish & See Score 0 of 3 checked ← Back 1 / 3 1 2 3
