Unit of Current MCQs

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Unit of Current is Ampere. Ampere is the SI unit of current. It forms one of the fundamental units of physical quantities. Ampere is denoted by A. Electric current is the rate of flow of charge. The value of the charge of an electron e is 1.602 x 176634 ×10^-19. Unit of current is very important to know to solve problems related to Current Electricity.

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MCQs on Unit of Current

Ques 1. What is the unit of current?

Ampere
Volt
Ohm
Watt

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Answer: a

Explanation: SI unit of electric current is Ampere. Ampere is the flow of electric charge at the rate of 1 coulomb per second. Ampere is denoted by the symbol A. Electric current is measured by a device called Ammeter.

Ques 2. Electric pressure is also called?

Resistance
Voltage
Wattage
Power

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Answer: b

Explanation: Voltage is defined as the work needed per unit of charge to move a test charge between the two points. It is also called electric potential difference, electric pressure or electric tension is the difference in electric potential between two points.

Ques 3. Materials that offer less resistance and enables free movement of electrons is called?

Conductors
Insulators
Semiconductor
Inductors

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Answer: a

Explanation: Conductors are materials that have free electrons which enables them to conduct electricity.

Ques 4. Which one is a poor conductor of electricity?

Iron
Silver
Wood
Tungsten

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Answer: c

Explanation: Wood is a non-conductive material and thus acts as an insulator. Most of the metals are very good conductors of electricity.

Ques 5. The property by which a material allows current to pass through it is called?

Resistance
Reactance
Capacitance
Conductance

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Answer: d

Explanation: Conductance is the property of a material to conduct electricity. Conductivity is amount or effective current a material can conduct. It is denoted by σ.

Ques 6. Conductance is the reciprocal of?

Resistance
Reactance
Capacitance
Conductance

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Answer: a

Explanation: Conductance is the property of a material to conduct electricity. On the other hand, resistance is the property of a material to resist the electric current from passing through it.

Ques 7. Resistance varies inversely with?

Length
Cross section
Temperature
Resistivity

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Answer: b

Explanation: Resistance is directly proportional to resistivity and length. It is inversely proportional to cross sectional area of the conductor.

R = $\frac{pL}{A}$ p = resistivity, L = length, A = cross sectional area

Ques 8. Which instrument is used to detect electric current?

Galvanometer
Wattmeter
Rheostat
Voltmeter

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Answer: a

Explanation: Galvanometer is a device used to measure electric current and intensity. It is indicated by a magnetic needle's movement or that of a coil in a magnetic field. A galvanometer is also used as an ammeter and a voltmeter.

Ques 9. Calculate the voltage across a 33 ohm resistor carrying 2A current.

33V
46V
66V
99V

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Answer: c

Explanation: By Ohm’s law,

V = IR

V = 2 x 33

V = 66 volts

Ques 10. Calculate the resistance of a light bulb if its voltage is 5V and carries a current 10A.

0.2 Ohms
0.1 Ohms
0.5 Ohms
2 Ohms

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Answer: c

Explanation: By Ohm’s law,

V = IR

R = V/I

R = 5/10

R = 0.5 Ohms

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CBSE CLASS XII Related Questions

1.
Capacitors are manufactured with certain standard capacitances and working voltages. However, these standard values may not be the ones that are actually needed in a particular application. Two or more capacitors can be grouped in series or in parallel to achieve desired capacitance and voltage. When connected in series, the total capacitance decreases while the voltage rating increases, whereas in parallel connections, the total capacitance increases and maintains the same voltage rating. A capacitor stores energy in the electric field between its plates and stored energy is proportional to the square of the voltage and capacitance $U = \frac{1}{2}CV^2$, where symbols have their usual meanings.
Two capacitors, one of $3 \ \mu$F and the other of $6 \ \mu$F, are connected in series in the circuit as shown in the figure, for a long time. }

2.
A charged particle $+q$ in an electric field $\vec{E}$ experiences a force in the direction of the electric field. As a result, its kinetic energy changes. Similarly, the charged particle also experiences a force when it moves in a magnetic field $\vec{B}$. But this magnetic force is perpendicular to both velocity $\vec{v}$ of the charged particle and the magnetic field $\vec{B}$, so it cannot change the kinetic energy of the charged particle. Consider two charged particles 1 and 2 of masses $m$ and $\frac{m}{2}$ having charges $-q$ and $+2q$ respectively. They are accelerated from rest through the same potential difference $V$ and acquire kinetic energy $K_1$ and $K_2$. Then they enter in a region of uniform magnetic field $\vec{B}$ perpendicular to their velocities.

3.
Derive an expression for the capacitance of a parallel plate capacitor of plate area A and plate separation d with air present between the plates.

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4.
With the help of a labelled diagram, explain the principle, construction and working of an a.c. generator.

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5.
Read the following paragraph and answer the questions that follow.
In an experiment with convex lens of focal length f, the screen is fixed at a distance D from the object. A student slowly moves the lens away from the object towards the screen and finds that she is able to form sharp image of the object for two positions of the lens. The distance between these two positions of the lens is d.

6.
Two metal spheres of radii $r_1$ and $r_2$ ($> r_1$) having charges $q_1$ and $q_2$ respectively kept in air, are brought in contact. Which of the following statements is not correct ?

The total charge of the two spheres is conserved.
Both spheres attain the same potential.
The final potential of the system equals $\frac{1}{4\pi\epsilon_0} \frac{(q_1 + q_2)}{(r_1 + r_2)}$
The final potential of the system equals $\frac{1}{4\pi\epsilon_0} \frac{(q_1 + q_2) (r_1 + r_2)}{r_1 r_2}$

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Unit of Current MCQs

MCQs on Unit of Current

CBSE CLASS XII Related Questions

3.
Derive an expression for the capacitance of a parallel plate capacitor of plate area A and plate separation d with air present between the plates.

4.
With the help of a labelled diagram, explain the principle, construction and working of an a.c. generator.

6.
Two metal spheres of radii $r_1$ and $r_2$ ($> r_1$) having charges $q_1$ and $q_2$ respectively kept in air, are brought in contact. Which of the following statements is not correct ?

Similar Physics Concepts

Comments

dOGVmW

Unit of Current MCQs

MCQs on Unit of Current

CBSE CLASS XII Related Questions

3.Derive an expression for the capacitance of a parallel plate capacitor of plate area A and plate separation d with air present between the plates.

4.With the help of a labelled diagram, explain the principle, construction and working of an a.c. generator.

6.Two metal spheres of radii $r_1$ and $r_2$ ($> r_1$) having charges $q_1$ and $q_2$ respectively kept in air, are brought in contact. Which of the following statements is not correct ?

Similar Physics Concepts

Comments

dOGVmW

3.
Derive an expression for the capacitance of a parallel plate capacitor of plate area A and plate separation d with air present between the plates.

4.
With the help of a labelled diagram, explain the principle, construction and working of an a.c. generator.

6.
Two metal spheres of radii $r_1$ and $r_2$ ($> r_1$) having charges $q_1$ and $q_2$ respectively kept in air, are brought in contact. Which of the following statements is not correct ?