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#### New syllabus creative multiple choice questions physics

12th Standard EM

Reg.No. :
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Physics

Use Blue pen only
Time : 00:10:00 Hrs
Total Marks : 20

Part - A

Answer each of the following questions

20 x 1 = 20
1. The figure shows tow parallel equipotential surface A and B kept at a small distance 'r' a part from each other. A point change of Q coulomb is taken from the surface A to B. The amount of net work done will be

(a)

$W=\frac { -1 }{ 4\pi { \varepsilon }_{ 0 }r } \frac { q }{ r }$

(b)

$W=\frac { 1 }{ 4\pi { \varepsilon }_{ 0 }r } \frac { q }{ r }$

(c)

$W=\frac { -1 }{ 4\pi { \varepsilon }_{ 0 }r } \frac { q }{ r^2 }$

(d)

zero

2. The given figure is a plot of lines of force due to two charges q1 & q2 find out the sign of charges

(a)

both negative

(b)

both positive

(c)

upper positive and lower negative

(d)

upper negative and lower positive

3. An uncharged metal sphere is placed between two equal and oppositely charged metal plates. The nature of lines of force will be

(a)

(b)

(c)

(d)

4. An isolated metal sphere of radius 'r' is given a charge' q'. The potential energy of the sphere is

(a)

$\frac { { q }^{ 2 } }{ 4\pi { \varepsilon }_{ 0 }r }$

(b)

$\frac { { q }^{ } }{ 4\pi { \varepsilon }_{ 0 }r }$

(c)

$\frac { { q }^{ } }{ 8\pi { \varepsilon }_{ 0 }r }$

(d)

$\frac { { q }^{ 2 } }{ 8\pi { \varepsilon }_{ 0 }r }$

5. In a hydrogen atom the electron revolves around the proton in an orbit of 0.53 $\mathring { A }$. The potential produced by the electron on the nuleus is

(a)

6.8 V

(b)

13.6 V

(c)

54.4 V

(d)

27.2 V

6. Eight mercury droplets having a radius of 1 mm and charge of 0.066 pC each merge to form one droplet. Its potential is

(a)

2.4 V

(b)

1.2 V

(c)

3.6 V

(d)

4.8 V

7. A force of 40 N is acting between two charges in air if the space between then is filled with glass εr = 8. Then the force between then is

(a)

20 N

(b)

10 N

(c)

5 N

(d)

the same and does not change

8. The concept of 'Field' was introduced by

(a)

(b)

Gauss

(c)

Maxwell

(d)

None

9. The force experienced by a unit charge is called

(a)

Electric potential

(b)

Electric flux

(c)

Electric field

(d)

Static electricity

10. The expression for electric field in vector form is

(a)

$\frac { 1 }{ 4\pi { \varepsilon }_{ 0 }r } \frac { q }{ r } \hat { r }$

(b)

$\frac { -1 }{ 4\pi { \varepsilon }_{ 0 }r } \frac { q }{ r } \hat { r }$

(c)

$\frac { -1 }{ 4\pi { \varepsilon }_{ 0 }r } \frac { q }{ r^2 } \hat { r }$

(d)

$\frac { 1 }{ 4\pi { \varepsilon }_{ 0 }r } \frac { q }{ r^2 } \hat { r }$

11. Which one of these is a vector quantity?

(a)

Electric charge

(b)

Electric field

(c)

Electric flux

(d)

Electric potential

12. The electric field created by a _________ is basically a non-uniform electric field.

(a)

Test charge

(b)

Positive charge

(c)

Negative charge

(d)

Point charge

13. The electric potential V as a function of distance x (metres) is given by V = ( 5x2 + 10x -9) volt. The value of electric field at a point x = 1m is

(a)

20 Vm-1

(b)

6 Vm-1

(c)

11 Vm-1

(d)

-23 Vm-1

14. Two condensers (capacitors) of capacity C1 and C2 are connected in parallel. A charge Q given to then is shared. The ratio of the charges Q is

(a)

$\frac { { C }_{ 2 } }{ { C }_{ 1 } }$

(b)

$\frac { { C }_{ 1 } }{ { C }_{ 2 } }$

(c)

C1.C2

(d)

$\frac { 1 }{ { C }_{ 1 }\times { C }_{ 2 } }$

15. What will happen if two conducting spheres are separately charged and then brought in contact?

(a)

Total charge on the two spheres is conserved

(b)

The total energy is conserved

(c)

Both charge and energy are conserved

(d)

The final potential is the mean of the original potentials.

16. A condenser is charged to a potential of 200V and has a charge of 0.1C. The energy stored in it is

(a)

1 J

(b)

2 J

(c)

10 J

(d)

20 J

17. Increasing the charge on the plates of a capacitor means

(a)

increasing the capacitance

(b)

increasing the potential difference between the plates

(c)

both (a) and (b) above

(d)

none of the above

18. A positively charged body 'A' has been brought near a brass cylinder 'B' mounted on a glass stand as shown in the figure. The potential of 'B' will be

(a)

zero

(b)

Negative

(c)

positive

(d)

Infinite

19. Four plates each of area 'N. and inferplate separation 'd' are placed as shown in figure. The two inner plates are connected to the point 'B' and outer to point 'A'. What is equivalent capacitance?

(a)

$\frac { { \varepsilon }_{ 0 }A }{ d } \\$

(b)

$\frac { {2 \varepsilon }_{ 0 }A }{ d } \\$

(c)

$\frac { {3 \varepsilon }_{ 0 }A }{ d } \\$

(d)

$\frac { {4 \varepsilon }_{ 0 }A }{ d } \\$

20. Charge per unit volume is called

(a)

Linear charge density (λ)

(b)

Surface charge density (σ)

(c)

Volume charge density (ρ)

(d)

Electric flux