Capacitors

The capacitance of a parallel plate capacitor depends on

• the type of metal used

• the thickness of plates

• the potential applied across the plates

• the separation between the plates

The capacitance of a parallel plate capacitor is C . Its capacitance when the separation between the plates is halved will be

• 4C

• 2C

• C/2

• C/4

When a slab of dielectric is introduced between the parallel plates of a capacitor which remains connected to a battery, then charge on the capacitor will

• decrease

• remain unchanged

• increase

• depends on the nature of the dielectric introduced

In the RC circuit, the time constant (τ) for the circuit is:

• τ = R × C

• τ = R / C

• τ = C / R

• τ = R² × C

During charging of a capacitor, the variation of its p.d. V with time t is shown as

• 
• 
• 
• 

The energy of a charged capacitor is given by the expression (q= charge on the conductor and C = its capaciance)

• $\frac{q^2}{2C}$

• $\frac{q^2}{C}$

• $\frac{q^{ }}{2C^2}$

•  $2qC$  
  

Change Q on a capacitor varies with voltage V as shown. The area of triangle OAB represents

• capacitance of the capacitor

• electric charge on the capacitor

• electric field between the plates

• energy stored in the capacitor

Three equal capacitors, each with capacitance are connected as shown in figure. Then the equivalent capacitance between and is

• C

• C/3

• 3C

• 3C/2

The equivalent capacitance avross A and B in the figure is equal to

• 1 $\mu$ F

• 3 $\mu$ F

• 2 $\mu$ F

• 1.5 $\mu$ F

Two capacitors  $C_1$  and  $C_2$  of capacitances C and 2C respectively are connected in series. A voltage of 6 V is applied across them. The ratio of energy stored in  $C_1$  to that of  $C_2$  is 

• 1 : 2

• 2 : 1 

• 1 : 4

• 4 : 1