The resistance of a conducting wire is directly proportional to its MCQ with Answer and Explanation

Explanation:
Resistance (R) of a wire is given by R = ρL/A, where ρ is resistivity, L is length, and A is cross-sectional area. If L becomes 2L and A becomes 2A, the new resistance is R' = ρ(2L)/(2A). The 2s cancel out, leaving R' = ρL/A = R. Thus, the resistance remains entirely unchanged.

Explanation:
Polarization possible only for transverse waves (oscillations ⊥ propagation). Longitudinal waves (sound) cannot be polarized. Memory aid: 'Polarization ⇒ transverse nature; light is EM transverse wave'. Wave property frequently tested in competitive exams.

Explanation:
Pressure = Force/Area. Force = mass × acceleration, dimensions [MLT⁻²]. Area = L². So pressure = [MLT⁻²]/[L²] = [ML⁻¹T⁻²]. This is also the dimension of stress. Common exam trap: confuse with energy density which is also [ML⁻¹T⁻²].