In an electrical circuit two resistors of 2 Ω and 4 Ω respectively are connected in series to a 6 V battery. The heat dissipated by the 4 Ω resistor in 5 s will be [NCERT Exemplar Problems] (a) 5 J (b) 10 J (c) 20 J (d) 30 J

nswer: c Explanation: (c) Total resistance of the combination Rs = 2 + 4 = 6 Ω Current, I = $$\frac{V}{R_{s}}=\frac{6}{6}$$= 1 Heat dissipation in 4 Ω resistor, H = I²Rt= 1² × 4 × 5 = 20 J