According to Joule's law of heating, the heat produced in a resistor is directly proportional to the square of: MCQ with Answer and Explanation

Explanation:
Horizontal range R = u²sin(2θ)/g. sin(2θ) is maximum (value 1) when 2θ = 90° ⇒ θ = 45°. Thus maximum range at 45° projection angle, assuming same initial speed and level ground. Memory tip: 'Max range at 45°; max height at 90°'. This standard projectile motion result is frequently tested in competitive exams. Always verify assumptions: no air resistance, uniform gravity, launch and landing at same height. For different heights, optimal angle differs.

Explanation:
Work W = F·d = Fd cosθ. cos0° = 1 gives maximum work. At 90°, cos90° = 0, work zero. For given magnitudes, maximum when force parallel to displacement. This is basic definition.

Explanation:
T ∝ √l. If l' = 4l, T' = √4 × T = 2T. Period doubles when length quadruples. Memory aid: 'Pendulum: T ∝ √l; 4× length ⇒ 2× period'. Proportional reasoning frequently tested in competitive oscillations sections.