### Physics - Electrostatistics

#### Question - 1

A charge +q located at O is placed midway between two charges of +q each.All the three charges lie on a straight line. The charge at O

• A will be in unstable equilibrium
• B will be in stable equilibrium
• C will not be in stable equilibrium
• D will move laterally along the right bisector of the line

#### Question - 2

A wimshurst machine cannot work in vacuum because

• A there is no air
• B air is a bad conductor of electricity
• C there is no mutual collision of molecules
• D there is optimum pressure of air required for its operation
• E Charge is produced by conduction

#### Question - 3

Electric potential difference is defined as the

• A Scalar function of position
• B single-valued scalar function of two positions
• C potential energy of a system of charges
• D potential associated with the electric field

#### Question - 4

The edge effect in a parallel plate capacitor can be made negligibly small if

• A the separation between the two plates is small
• B the separation is small and area of the plates is large
• C the area of the plates is large
• D the separation is large and area is small

#### Question - 5

The variation of potential energy V(r) as a function of distance of separation(r) for a proton p and an electron e is given by the graph

• A
• B
• C
• D

#### Question - 6

A parallel plate capacitor has charge +Q and -Q on its plate.The separation between the plates is doubled

• A charge on the plates is reduced to half
• B capacitance is doubled
• C Potential difference between the plates is doubled
• D Electric field between the plates is reduced to half

#### Question - 7

The dimensional formula for electric field strength is

• A $ML{ T }^{ -2 }{ I }^{ -1 }$
• B $ML ^ { -1 }{ T }^{ -3 }{ I }^{ -1 }$
• C $ML{ T }^{ -2 }{ I }$
• D $ML{ T }^{ -3 }{ I }^{ -1 }$

#### Question - 8

A parallel plate capacitor stores its electrical energy in

• A the plate at higher potential
• B the plate at lower potential
• C the potential difference between the two plates
• D the electric field between the two plates

#### Question - 9

Two capacitors of capacitance 3$\mu F$ and 6$\mu F$ are connected in series across a 12V battery.They are then disconnected from the battery and connected together in parallel.The resulting potential difference will be

• A 12 V
• B 6 V
• C 5.6 V
• D 8 V

#### Question - 10

How many time constants must elapse before a capacitor in an RC circuit is charged to within 1% of its equilibrium charge?

• A 0.868
• B 2
• C 1.152
• D 4.606