Polarization is a property unique to transverse waves, so observation of polarization shows light is transverse.

Plucking at the middle predominantly excites the fundamental mode with one loop (one antinode at center).

At extreme position (X = ±A), instantaneous velocity is zero (minimum), so both statements match.

v_max = 2πf A = 2π×2.5×0.020 ≈ 0.314 m/s.

Beat frequency is 1/22 s⁻¹ = 0.04545 Hz; f1 = 1/2 = 0.5 Hz, so f2 = 0.5 + 0.04545 = 0.54545 Hz and T = 1/f2 ≈ 1.83 s.

Oscillatory motion inherently involves a restoring force opposing displacement together with inertia that causes oscillation.

The standard formula for wave speed on a stretched string is v = sqrt(tension/mass per unit length), so option A is correct (OCR answer key).

A wavefront is the surface joining all points having the same phase of oscillation.

Wavelength λ = v / f = 10 m/s ÷ 100 Hz = 0.1 m = 10 cm.

x = A(sin ωt + cos ωt) can be written as a single sinusoid with amplitude A√(1^2+1^2) = A√2, so option D is correct.