A 750   Hz ,   20   V rms source is connected to a resistance of 100   Ω , an…

750 Hz, 20 Vrms source is connected to a resistance of 100 Ω, an inductance of 0.1803 H and a capacitance of 10 μF all in series. The time in which the resistance (heat capacity  2 J/°C ) will get heated by 10°C. (assume no loss of heat to the surroundings) is close to :
  1. 418 s
  2. 245 s
  3. 365 s
  4. 348 s

Solution

The AC circuit is shown below.

Here,R=100, XL=Lω=0.1803×750×2π=850Ω

The capacitive reactance Xc=1=110-5×2π×750=21.23 Ω

Total impedance Z=R2+XL-XC2

=1002+850-21.232=834.77835

The heat loss H=irms2Rt=mst

20835×20835×100t=2×10

t=348.61 sec

Asked in: JEE Main 2020 (03 Sep Shift 1)

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