Fuse protects circuit by: MCQ with Answer and Explanation

Explanation:
In a parallel-sided glass slab, refraction at first surface bends ray towards normal; at second surface (glass to air), it bends away by equal angle, making emergent ray parallel to incident ray but shifted laterally. No net deviation, only displacement. Memory aid: 'Slab: emergent ray parallel to incident; prism: emergent ray deviated'. This ray optics concept is frequently tested in competitive exams. Always distinguish slab (parallel faces) from prism (non-parallel faces) behavior: slab causes lateral shift, prism causes angular deviation.

Explanation:
For a circular coil with N turns, magnetic field at center B = μ₀NI/(2R). For single turn (N=1), B = μ₀I/(2R). This derives from Biot-Savart law. Option A is for single turn; B and D have incorrect constants. Memory tip: 'Coil center: B = μ₀NI/(2R); straight wire: B = μ₀I/(2πr)'. This formula application is frequently tested in magnetism sections of competitive exams. Always note number of turns N; competitive exams often include it to test attention to detail.

Explanation:
For resistors in parallel, the reciprocal of the equivalent resistance (1/Rp) is the sum of the reciprocals of individual resistances. 1/Rp = 1/R1 + 1/R2 + 1/R3 = 1/2 + 1/3 + 1/6. Finding a common denominator (6): 1/Rp = 3/6 + 2/6 + 1/6 = 6/6 = 1. Therefore, Rp = 1 Ω.