The charge flowing through a resistance R varies with time t as Q = a t - b t 2 where a and b are positive…

The charge flowing through a resistance R varies with time t as Q=at-bt2 where a and b are positive constants. The total heat produced in R is:
  1. a3R6b
  2. a3R3b
  3. a3R2b
  4. a3Rb

Solution

given 

Q=at-bt2
i=dqdt=a-2bt
i=0
at t= a 2b
dH=i2Rdt
=a-2bt2R dt
H=0a2ba-2bt2 R dt
=a-2bt3R3-2b0a2b
=1-6ba-2ba2b3-a3R
=-16b03-a3R
H= a 3 R 6b

Asked in: NEET 2016 (Phase 1)

Practice more Current Electricity questions on Aicharya