Pressure cooker cooks food faster because MCQ with Answer and Explanation

Explanation:
Equilibrium occurs where the net force is zero, meaning dU/dx = 0. Given U(x) = ax^2 - bx, taking the derivative: dU/dx = 2ax - b = 0. Therefore, x = b / 2a. To confirm it's stable, the second derivative d^2U/dx^2 must be positive. d^2U/dx^2 = 2a. Assuming 'a' is positive, it represents a stable equilibrium point.

Explanation:
Nichrome (alloy of nickel, chromium) has high resistivity and high melting point, doesn't oxidize easily at high temperature. Copper has low resistivity, not suitable for heating element.

Explanation:
Power = 1 kW (1000 W). Time = 2 h. Energy = Power × time = 1 × 2 = 2 kWh. 1 kWh = 3.6 × 10⁶ J, but here answer in kWh. Commercial unit.