The greenhouse effect is mainly due to increase in MCQ with Answer and Explanation

Explanation:
Power = work done per unit time = kinetic energy imparted per second. KE per bullet = ½mv² = ½×0.01×(600)² = 1800 J. Bullets per second = 60/60 = 1. Thus power = 1800 J/s = 1800 W. Note: Mass conversion: 10 g = 0.01 kg. This problem combines kinetic energy formula with power definition. Exam tip: Always convert to SI units first (grams to kg, minutes to seconds). Such numerical problems test multi-step calculation skills and unit conversion proficiency essential for competitive examinations.

Explanation:
Work done (W) is calculated as the dot product of force and displacement: W = F × d × cos(θ). Since the displacement is in the direction of the force, the angle θ is 0°, and cos(0°) = 1. W = 10 N × 2 m × 1 = 20 Joules (J).

Explanation:
1/R_eq = 1/3 + 1/3 + 1/3 = 1 ⇒ R_eq = 1Ω. For n equal resistors in parallel: R_eq = R/n. Memory tip: 'Parallel: reciprocal sum; result < smallest resistor'. Basic circuit calculation frequently tested in competitive exams to verify parallel combination formula.