The human eye lens is MCQ with Answer and Explanation

Explanation:
Fuse is a safety device with a wire that melts when current exceeds rated value, breaking the circuit and preventing damage from overcurrent/short circuits. It operates on Joule heating (I²R). Option A is opposite; C describes capacitor; D describes rectifier. Memory tip: 'Fuse = sacrificial overcurrent protector'. This practical application question tests knowledge of electrical safety devices, frequently examined in competitive exams. Always link fuse rating to circuit requirements: fuse current rating slightly above normal operating current.

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:
Gamma rays highest penetration, alpha least.