PrepBharat

1. An electron enters between two horizontal plates separated by 2mm and having a potential difference of 1000V. The force on electron is
a) \[8\times 10^{-12} N\]
b) \[8\times 10^{-14} N\]
c) \[8\times 10^{9} N\]
d) \[8\times 10^{14} N\]

View Answer

2.Electric charges of \[+10\mu C,+5\mu C,-3\mu C\]     and \[+8\mu C\]   are placed at the corners of a square of side \[\sqrt{2}m\]   . the potential at the centre of the square is
a) 1.8 V
b) \[1.8\times 10^{6} V\]
c) \[1.8\times 10^{5} V\]
d) \[1.8\times 10^{4} V\]

View Answer

3.What is the magnitude of a point charge which produces an electric field of 2 N/coulomb at a distance of 60 cm \[\left(1/4\pi\epsilon_{0}=9\times 10^{9} N-m^{2}/C^{2}\right)\]
a) \[8\times 10^{-11} C\]
b) \[2\times 10^{-12} C\]
c) \[3\times 10^{-11} C\]
d) \[6\times 10^{-10} C\]

View Answer

4. The electric field due to a charge at a distance of 3 m from it is 500 N/coulomb. The magnitude of the charge is \[\left(\frac{1}{4\pi\epsilon_{0}}=9\times 10^{9} \frac{N-m^{2}}{coulomb^{2}}\right)\]
a) 2.5 micro-coulomb
b) 2.0 micro-coulomb
c) 1.0 micro-coulomb
d) 0.5 micro-coulomb

View Answer

5. Two charges of \[4\mu C\]  each are placed at the corners A and B of an equilateral triangle of side length 0.2 m in air. The electric potential at C is \[\left(\frac{1}{4\pi\epsilon_{0}}=9\times 10^{9} \frac{N-m^{2}}{C^{2}}\right)\]
a) \[9\times 10^{4} V\]
b) \[18\times 10^{4} V\]
c) \[36\times 10^{4} V\]
d) \[36\times 10^{-4} V\]

View Answer

6.Electric field strength due to a point charge of \[5\mu C\]  at a distance of 80 cm from the charge is
a) \[8\times 10^{4} N/C\]
b) \[7\times 10^{4} N/C\]
c) \[5\times 10^{4} N/C\]
d) \[4\times 10^{4} N/C\]

View Answer

7.Ten electrons are equally spaced and fixed around a circle of radius R. Relative to V = 0 at infinity, the electrostatic potential V and the electric field E at the centre C are
a) \[ V\neq 0\]   and \[\vec{E}\neq 0\]
b) \[ V\neq 0\]   and \[\vec{E}= 0\]
c) V= 0 and \[\vec{E}= 0\]
d) V= 0 and \[\vec{E}\neq 0\]

View Answer

8. Two positive point charges of 12 \[\mu C\]  and 8 \[\mu C\]  are 10cm apart. The work done in bringing them 4 cm closer is
a) 5.8 J
b) 5.8 eV
c) 13 J
d) 13 eV

View Answer

9.Three identical point charges, as shown are placed at the vertices of an isosceles right angled triangle. Which of the numbered vectors coincides in direction with the electric field at the midpoint M of the hypotenuse

a) 1
b) 2
c) 3
d) 4

View Answer

10. The displacement of a charge Q in the electric field \[E=e_{1}\hat{i}+e_{2}\hat{j}+e_{3}\hat{k}\]      is   \[\hat{r}=a\hat{i}+b\hat{j}\]     . The work done is
a) \[Q\left(ae_{1}+be_{2}\right)\]
b) \[Q\sqrt{\left(ae_{1}\right)^{2}+\left(be_{2}\right)^{2}}\]
c) \[Q\left(e_{1}+e_{2}\right)\sqrt{a^{2}+b^{2}}\]
d) \[Q\left(\sqrt{e_1^2+e_2^2}\right)\left(a+b\right)\]

View Answer