Electrostatics & Capacitors · JEE Main previous year questions

2006 4 questions

1. Q552006 · 29 Apr 2006 · Shift 1

   Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature $T_0$, while Box contains one mole of helium at temperature $(\frac{7}{3})T_0$. The boxes are then put into thermal contact with each other, and heat flows between them until the gases reach a common final temperature (ignore the heat capacity of boxes). Then, the final temperature of the gases, $T_f$ in terms of $T_0$ is

   1. A.$T_f=\frac{3}{7}{T}_0$
   2. B.$T_f=\frac{7}{3}{T}_0$
   3. C.$T_f=\frac{3}{2}{T}_0$
   4. D.$T_f=\frac{5}{2}{T}_0$
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   Answer: C

2. Q612006 · 29 Apr 2006 · Shift 1

   An electric dipole is placed at an angle of $30^{\circ }$ to a non-uniform electric field. The dipole will experience

   1. A.a translation force only in the direction of the field
   2. B.a translation force only in a direction normal to the direction of the field
   3. C.a torque as well as a translational force
   4. D.a torque only
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   Answer: C

3. Q622006 · 29 Apr 2006 · Shift 1

   Two spherical conductors $A$ and $B$ of radii $1mm$ and $2mm$ are separated by a distance of $5cm$ and are uniformly charged. If the spheres are connected by a conducting wire then in equilibrium condition, the ratio of the magnitude of the electric fields at the surfaces of spheres $A$ and $B$ is

   1. A.$4:1$
   2. B.$1:2$
   3. C.$2:1$
   4. D.$1:4$
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   Answer: C

4. Q852006 · 29 Apr 2006 · Shift 1

   The $rms$ value of the electric field of the light coming from the Sun is $720N/C$. The average total energy density of the electromagnetic wave is

   1. A.$4.58\times 10^{-6}J/{\mathrm{m}}^3$
   2. B.$6.37\times 10^{-9}J/{\mathrm{m}}^3$
   3. C.$81.35\times 10^{-12}J/{\mathrm{m}}^3$
   4. D.$3.3\times 10^{-3}J/{\mathrm{m}}^3$
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   Answer: A