A body starts from rest and moves with uniform acceleration a. The ratio of distances covered in the 1st, 2nd, and 3rd seconds of motion is: MCQ with Answer and Explanation

Explanation:
In hot deserts, the sand heats the air immediately above it, making it less dense (optically rarer) than cooler air higher up. Light from a tall object (like the sky or a tree) traveling downwards passes from denser to rarer air layers, bending away from the normal. Eventually, the angle of incidence exceeds the critical angle, causing total internal reflection. The observer perceives this reflected light as a pool of water on the ground.

Explanation:
An electric iron contains a heating element (usually nichrome). When electric current passes through this high-resistance element, it produces heat according to Joule's law (H = I²Rt). An electric fan uses the magnetic effect (motor), a generator uses electromagnetic induction, and a transformer uses mutual induction.

Explanation:
Volume V = a³. For error propagation: % error in V = 3 × % error in a. Given 2% error in side, volume error = 3×2% = 6%. Power rule: if Q = xⁿ, %ΔQ = |n|×%Δx. Memory tip: Volume depends on cube of length ⇒ errors triple. Common in experimental error analysis questions.