A condenser of capacitance C is fully charged by a 200 V supply. It is then discharged through a small coil of resistance wire embedded in thermally insulated block of specific heat 250 J / kg − K and

Question

A condenser of capacitance C is fully charged by a 200 V supply. It is then discharged through a small coil of resistance wire embedded in thermally insulated block of specific heat 250 J / kg − K and of mass 100 g . If the temperature of the block rises by 0.4 K , then the value of C is

TestHub · Accepted Answer

The energy stored in the capacitor U = 2 1 ​ CV 2 = 2 1 ​ C × ( 200 ) 2 = 2 C × 1 0 4 J This energy is used to heat up the block. Let Δ θ be the rise in temperature, then heat energy Q = ms Δ θ = 0.1 × 250 × 0.4 = 10 J ⇒ ​ Now, 2 C × 1 0 4 = 10 C = 2 × 1 0 4 10 ​ = 5 × 1 0 − 4 = 500 μ F ​

Physics - Capacitor Question with Solution | TestHub

Options:

Doubts & Discussion