Current Electricity · JEE Main previous year questions

2009 3 questions

1. Q372009 · 27 Apr 2009 · Shift 1

   Statement - 1: The temperature dependence of resistance is usually given as $R=R_0(1+\alpha \Delta t)$. The resistance of wire changes from $100\Omega$ to $150\Omega$ when its temperature is increased from $27^{\circ }C$ to $227^{\circ }C$. This implies that $\alpha =2.5\times 10^{-3}/C$. Statement - 2: $R=R_0(1+\alpha \Delta t)$ is valid only when the change in the temperature $\Delta T$ is small and $\Delta T=(R-R_0)<<R_0$.

   1. A.Statement - 1 is true, Statement - 2 is true; Statement - 2 is the correct explanation of Statement - 1
   2. B.Statement - 1 is true, Statement - 2 is true; Statement - 2 is not the correct explanation of Statement - 1
   3. C.Statement - 1 is false, Statement - 2 is true
   4. D.Statement - 1 is true, Statement - 2 is false
   Show answer

   Answer: C

2. Q522009 · 27 Apr 2009 · Shift 1
   
   1. A.$\frac{12}{t}{e}^{-3t}V$
   2. B.$6\left(1-e^{-t/0.2}\right)V$
   3. C.$12e^{-5t}V$
   4. D.$6e^{-5t}V$
   Show answer

   Answer: C

3. Q572009 · 27 Apr 2009 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
   Show answer

   Answer: D