Two coils connected in series have resistance of `600K Omega` and `300 Omega` at `20^@C` and temperature coefficient of` 0.001` and `0.004 (.^@C)^-1` respectively. Find resistance of the combination at a temperature of `50^@C`. What is the effective temperature coefficient of combination?

Answer

A, B, C, D

Explanation

In sereis
`alpha_(eq)=(R_(01)alpha_1+R_(02)alpha_2)/(R_(01)+R_(02))`
`=((600)(0.001)+(300)(0.004))/(600+300)`
`=0.002per^@C`
`Now, R_t=R_0[1+alpha/_\theta]`
`=(600+300)[1+0.002xx30]=954Omega`