#### Electrostatics One Mark Questions

12th Standard EM

Reg.No. :
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Physics

Time : 00:30:00 Hrs
Total Marks : 10
5 x 1 = 5
1. An electric dipole is placed at an alignment angle of 300 with an electric fi eld of 2 × 105 NC-1. It experiences a torque equal to 8 N m. Th e charge on the dipole if the dipole length is 1 cm is

(a)

4 mC

(b)

8 mC

(c)

5 mC

(d)

7 mC

2. The total electric fl ux for the following closed surface which is kept inside water

(a)

$\frac { 80q }{ { \varepsilon }_{ 0 } }$

(b)

$\frac { q }{ { 40\varepsilon }_{ 0 } }$

(c)

$\frac { q }{ { 80\varepsilon }_{ 0 } }$

(d)

$\frac { q }{ { 160\varepsilon }_{ 0 } }$

3. An electric field $\vec { E } =10x\hat { i }$ exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:

(a)

10 J

(b)

-20 J

(c)

+20 J

(d)

-10 J

4. The value of constant 'K' in coulomb law is

(a)

0.9 x 109 Nm2 C2

(b)

9 x 10-9 Nm2C2

(c)

9 x 109 Nm-2 C-2

(d)

9 x 109 Nm2 C-2

5. The electrostatic force is always greater in magnitude than gravitational force for_________ object.

(a)

bigger size

(b)

smaller size

(c)

medium size

(d)

all the above

6. 5 x 1 = 5
7. Air

8. (1)

9. Dielectric

10. (2)

8.854 x 10-12 C2N-1m-2

11. Electrostatic shielding

12. (3)

Insulator

13. Electrostatic Induction

14. (4)

εr= 1

15. permittivity of free space

16. (5)

Van de graaff generator