Electrostatics & Capacitors · JEE Main previous year questions

2015 4 questions

1. Q362015 · 4 Apr 2015 · Shift 1

   A solid body of constant heat capacity $1\mathrm{J}{/}^{\circ }\mathrm{C}$ is being heated by keeping it in contact with reservoirs in two ways: $(i)$ Sequentially keeping in contact with 2 reservoirs such that each reservoir supplies same amount of heat. $(ii)$ Sequentially keeping in contact with 8 reservoirs such that each reservoir supplies same amount of heat. In both the cases body is brought from initial temperature $100^{\circ }\mathrm{C}$ to final temperature $200^{\circ }\mathrm{C}$. Entropy change of the body in the two cases respectively is :

   1. A.$\ln 2,2\ln 2$
   2. B.$2\ln 2,8\ln 2$
   3. C.$\ln 2,4\ln 2$
   4. D.$\ln 2,\ln 2$
   Show answer

   Answer: D

2. Q422015 · 4 Apr 2015 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
   Show answer

   Answer: D

3. Q432015 · 4 Apr 2015 · Shift 1

   A uniformly charged solid sphere of radius $R$ has potential $V_0$ (measured with respect to $\infty$) on its surface. For this sphere the equipotential surfaces with potentials $\frac{3V_0}{2}$, $\frac{5V_0}{4}$, $\frac{3V_0}{4}$ and $\frac{V_0}{4}$ have radius $R_1$, $R_2$, $R_3$ and $R_4$ respectively. Then

   1. A.$R_1=0\text{ and }{R}_2<(R_4-R_3)$
   2. B.$2R<R_4$
   3. C.$R_1=0\text{ and }{R}_2>(R_4-R_3)$
   4. D.$R_1\ne 0\text{ and }(R_2-R_1)>(R_4-R_3)$
   Show answer

   Answer: A, B

4. Q442015 · 4 Apr 2015 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
   Show answer

   Answer: C