The drift velocity vd of electrons in a conductor is given by the equation: vd = eEr/m Since E = V/L, we get: vd = eVr/mL Here, vd is directly proportional to the applied potential difference V. Thus, the correct ...
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The internal resistance r of the cell is given by: r=R l1/l2−1 Given l1 =120 cm, l2 = 40 cm and R=1Ω: r = 1 ×120/40 −1 = 2Ω Answer: (d) 2Ω. Class 12th Science Physics NCERT MCQ Questions NCERT Books ...
The energy dissipated as heat in a resistor is given by: Q = P × t where power P is: P = V²/R Given: V =15V,R=50Ω, t = 1 minute = 60 seconds. P = 15²/50 = 225/50 = ...
The heat produced by a heater is given by the formula: Q = P × t where: P = 100W,t = 2 minutes = 2 × 60 = 120 seconds Q = 100 × 120 =12,000 J = 12.0 kJ Answer: (c) 12.0 ...
In a potentiometer, the balancing length is proportional to the emf of the cell. Given V balances at l/3, for a cell of emf 1.5V, the new balancing length is (1.5V/V) × (l/3) = 2l/3. Answer: (d) 2l/3. Class 12th ...