The material of a permanent magnet should have MCQ with Answer and Explanation

Explanation:
Electric power P = VI. Thus I = P/V = 100 W / 220 V ≈ 0.4545 A ≈ 0.45 A. This direct application of power formula is fundamental in electricity. Memory tip: 'I = P/V for resistive loads'. Competitive exams frequently test such calculations with household appliance ratings. Always use consistent units (watts, volts, amperes). Note: This assumes purely resistive load (valid for incandescent bulbs); for motors or electronics, power factor may matter, but not at this level.

Explanation:
F = Gm₁m₂/r² ⇒ G = Fr²/(m₁m₂) = [MLT⁻²][L²]/[M²] = [M⁻¹L³T⁻²]. Memory aid: 'G dimensions: [M⁻¹L³T⁻²]; small value reflects weak gravity'. Dimensional analysis frequently tested in competitive exams.

Explanation:
Latent heat per unit mass, Q = mL => L = Q/m, unit J/kg (or cal/g). Specific latent heat. Not per degree.