A 12 V battery is connected across a series combination of 2 Ω, 3 Ω, 5 Ω resistors. Current is MCQ with Answer and Explanation

Explanation:
For a body at rest, displacement remains constant over time. The displacement-time graph is a horizontal line, parallel to time axis, indicating zero slope (velocity = 0). Option A indicates constant velocity. Option B (velocity-time zero slope) means constant velocity, not necessarily rest (could be constant non-zero velocity). Option D indicates acceleration. So C is correct.

Explanation:
Mirror formula: 1/f = 1/u + 1/v. Sign convention: f negative for concave mirror? Wait, standard Cartesian: f = -20 cm (concave), u = -30 cm (object real). Thus 1/(-20) = 1/(-30) + 1/v ⇒ -1/20 = -1/30 + 1/v ⇒ 1/v = -1/20 + 1/30 = (-3+2)/60 = -1/60 ⇒ v = -60 cm. Magnitude 60 cm, negative sign indicates real image in front of mirror. Many exams use magnitude-only options; here 60 cm is correct. Memory tip: 'Concave mirror: object beyond C (2f) ⇒ image between F and C, real, inverted'. This numerical tests mirror formula application with sign conventions, crucial for optics in competitive exams.

Explanation:
Candela (cd) is one of the seven SI base units, measures luminous intensity. Lumen is luminous flux (lm = cd·sr). Lux is illuminance (lx = lm/m²). Watt is power.