Current Electricity

1

A 3 volt battery with negligible internal resistance is connected in a circuit as shown in the figure. The current I, in the circuit will be

  1. 1.5 A
  2. 1 A
  3. 2 A
  4. 1/3 A
2

The current voltage relation of diode is given by I = (e1000V/T - 1) mA, where the applied voltage V is in volts and the temperature T is in degree Kelvin. If a student makes an error measuring ± 0.01 V while measuring the current of 5 mA at 300 K, what will be the error in the value of current in mA?

  1. 0.02
  2. 0.2
  3. 0.05
  4. 0.5
3

Let C be the capacitance of a capacitor discharging through a resistor R. Suppose t1 is the time taken for the energy stored in the capacitor to reduce to half its initial value and t2 is the time taken for the charge to reduce to one-fourth its initial value. Then the ratio t1/t2 will be

  1. 1/4
  2. 1/2
  3. 1
  4. 2
4

Capacitance (in F) of a spherical conductor with radius 1 m is

  1. 10-3
  2. 1.1 X 10-10
  3. 9 X 10-9
  4. 10-6
5

A parallel plate capacitor is made of two circular plates separated by a distance of 5 mm and with a dielectric of dielectric constant 2.2 between them. When the electric field in the dielectric is 3 × 104 V/m, the charge density of the positive plate will be close to

  1. 6 × 10–7 C/m2
  2. 6 × 104 C/m2
  3. 3 × 104 C/m2
  4. 3 × 10–7 C/m2
6

A galvanometer having a coil resistance of 100 Ω gives a full scale deflection, when a current of 1 mA is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of 10 A is:

  1. 2 Ω
  2. 0.1 Ω
  3. 3 Ω
  4. 0.01 Ω