WorksheetsCurrent electricity
Total questions: 30
Worksheet time: 23mins
- Kirchhoff's junction rule is a reflection of
Conservation of current density vector
Conservation of charge and no accumulation of charge at the the junction
the momentum with which a charged particle approaches a junction is unchanged as the charged particle leaves the junction
Conservation of energy
Which of the following characteristics of electrons determines the current in a conductor?
Drift velocity alone
Thermal velocity alone
Both A and B
Neither A nor B
------ is called the increase in resistance per unit original resistance per degree kelvin rise of temperature
Thermal velocity
temperature coefficient of electrical resistivity
temperature coefficient of electrical resistance
conducance
12. In a meter bridge, the point D is a neutral point (figure
(a) The meter bridge can have other neutral point for this set of resistances.
(b) When the jockey contacts a point on meter wire left of D, current flows to B from the wire.
(c) When the jockey contacts a point on the meter wire to the right of D, current flows from B to the wire through galvanometer.
(d) When R is increased, the neutral point shifts to left.
13. Drift velocity vd varies with the intensity of electric field as per the relation
(a) vd ∝ E
(b) vd ∝ 1/E
(c) vd = constant
(d) vd ∝ E²
14. For measurement of potential difference, a potentiometer is preferred over voltmeter because
(a) potentiometer is more sensitive than voltmeter.
(b) the resistance of potentiometer is less than voltmeter.
(c) potentiometer is cheaper than voltmeter.
(d) potentiometer does not take current from the circuit.
16. Which of the following I-V graph represents ohmic conductors?
(a) A
(b) B
(c) C
(d) D
20. The resistivity of alloy manganin is
(a) Nearly independent of temperature
(b) Increases rapidly with increase in temperature
(c) Decreases with increase in temperature
(d) Increases rapidly with decrease in temperature
18. In a Wheatstone bridge if the battery and galvanometer are interchanged then the deflection in galvanometer will
(a) change in previous direction
(b) not change
(c) change in opposite direction
(d) none of these.
19. n a potentiometer of 10 wires, the balance point is obtained on the 7th wire. To shift the balance point to 9th wire, we should
(a) decrease resistance in the main circuit.
(b) increase resistance in the main circuit.
(c) decrease resistance in series with the cell whose emf is to be measured.
(d) increase resistance in series with the cell whose emf is to be determined.
20. The figure below shows currents in a part of electric circuit. The current i is ________ .
(a) 2 A
(b) 1.3 A
(c) 1.7 A
(d) 1 A
21. In parallel combination of n cells, we obtain
(a) more voltage
(b) more current
(c) less voltage
(d) less current
- Kirchhoff's junction rule is a reflection of
Conservation of current density vector
Conservation of charge and no accumulation of charge at the the junction
the momentum with which a charged particle approaches a junction is unchanged as the charged particle leaves the junction
Conservation of energy
Which of the following characteristics of electrons determines the current in a conductor?
Drift velocity alone
Thermal velocity alone
Both A and B
Neither A nor B
By what percent the specific resistance of a conductor change when it is length is increased by two times.
10%
20%
5%
No change
A current of 5 Amp is allowed to flow through a wire of cross sectional area 5 mm2. What will be the current density if the area vector describes an angle of 900 to the electric current
2 x 10-5 Am-2
2 x 10-6 Am-2
5 x 10-5 Am-2
0
------ is called the increase in resistance per unit original resistance per degree kelvin rise of temperature
Thermal velocity
temperature coefficient of electrical resistivity
temperature coefficient of electrical resistance
conducance
When an electric field is applied across the ends of a conductor the electrons experience this..
gains kinetic energy due to electric field
loses kinetic energy due to electric field
loses / gains kinetic energy during the collision in the direction of electric field
loses/gains kinetic energy during the collision in the direction opposite to the direction of electric field
The average relaxation time during collision of electrons with atoms is
10-14 sec
10-10
104
1014
