Current Electricity Practice Test

12th Standard Physics — Current Electricity: Online Practice Test

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The following graph shows current versus voltage values of some unknown conductor. What is the resistance of this conductor?

மின்னழுத்த வேறுபாடு (V) மற்றும் மின்னோட்டம் (I) ஆகியவற்றிற்கு இடையேயான தொடர்பைக் காட்டும் வரைபடம்.

A.2 ohm B.4 ohm C.8 ohm D.1 ohm

A wire of resistance 2 ohms per meter is bent to form a circle of radius 1m. The equivalent resistance between its two diametrically opposite points, A and B as shown in the figure is

A மற்றும் B ஆகிய புள்ளிகளை நேர் எதிரே கொண்டுள்ள வட்ட வடிவக் கம்பிச் சுருள்.

A.\(\pi \Omega\) B.\(\frac{\pi}{2} \Omega\) C.\(2\pi \Omega\) D.\(\frac{\pi}{4} \Omega\)

A toaster operating at 240 V has a resistance of 120 \(\Omega\). Its power is

A.400 W B.2 W C.480 W D.240 W

A carbon resistor of (47 \(\pm\) 4.7 ) k \(\Omega\) to be marked with rings of different colours for its identification. The colour code sequence will be

A.Yellow – Green – Violet – Gold B.Yellow – Violet – Orange – Silver C.Violet – Yellow – Orange – Silver D.Green – Orange – Violet - Gold

What is the value of resistance of the following resistor?

பழுப்பு, கருப்பு, மஞ்சள் மற்றும் தங்க நிற வளையங்களைக் கொண்ட ஒரு கார்பன் மின்தடையாக்கி.

A.100 k \(\Omega\) B.10 k \(\Omega\) C.1 k \(\Omega\) D.1000 k \(\Omega\)

Two wires of A and B with circular cross section are made up of the same material with equal lengths. Suppose \(R_A = 3 R_B\), then what is the ratio of radius of wire A to that of B?

A.3 B.\(\sqrt{3}\) C.\(\frac{1}{\sqrt{3}}\) D.\(\frac{1}{3}\)

A wire connected to a power supply of 230 V has power dissipation \(P_1\). Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case power dissipation is \(P_2\). The ratio \(P_2/P_1\) is

A.1 B.2 C.3 D.4

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60W bulb for use in India is R, the resistance of a 60W bulb for use in USA will be

A.R B.2R C.\(\frac{R}{4}\) D.\(\frac{R}{2}\)

In a large building, there are 15 bulbs of 40 W, 5 bulbs of 100 W, 5 fans of 80 W and 1 heater of 1k W are connected. The voltage of electric mains is 220 V. The maximum capacity of the main fuse of the building will be

A.14 A B.8 A C.10 A D.12 A

Q10

There is a current of 1.0 A in the circuit shown below. What is the resistance of P?

9V மின்னழுத்த மூலம், 3 ஓம், R மற்றும் 2.5 ஓம் மின்தடையாக்கிகள் தொடரிணைப்பில் உள்ள ஒரு மின்சுற்று.

A.1.5 \(\Omega\) B.2.5 \(\Omega\) C.3.5 \(\Omega\) D.4.5 \(\Omega\)

Q11

What is the current drawn out from the battery?

5V மின்னழுத்த மூலத்துடன் பக்க இணைப்பில் இணைக்கப்பட்டுள்ள மூன்று 15 ஓம் மின்தடையாக்கிகள் கொண்ட மின்சுற்று.

A.1 A B.2 A C.3 A D.4 A

Q12

The temperature coefficient of resistance of a wire is 0.00125 per °C. At 20°C, its resistance is 1 \(\Omega\). The resistance of the wire will be 2 \(\Omega\) at

A.800 °C B.700 °C C.850 °C D.820 °C

Q13

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 \(\Omega\) is

A.0.2 \(\Omega\) B.0.5 \(\Omega\) C.0.8 \(\Omega\) D.1.0 \(\Omega\)

Q14

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

A.each of them increases B.each of them decreases C.copper increases and germanium decreases D.copper decreases and germanium increases

Q15

In Joule’s heating law, when R and t are constant, if the H is taken along the y axis and \(I^2\) along the x axis, the graph is

A.straight line B.parabola C.circle D.ellipse

Q16

Which of the following physical quantities is defined as the rate of flow of electric charges through a given cross-sectional area?

A.Electric potential B.Electric current C.Electrical resistance D.Electromotive force

Q17

By convention, the direction of conventional current in an external circuit is taken to be from:

A.The negative terminal to the positive terminal B.The direction of electron flow C.The positive terminal to the negative terminal D.Low potential to high potential

Q18

The average velocity acquired by electrons inside a conductor when subjected to an external electric field is called:

A.Terminal velocity B.Angular velocity C.Drift velocity D.RMS velocity

Q19

In the microscopic model of current, the relationship between current (\(I\)) and drift velocity (\(v_d\)) is given by:

A.\(I = neAv_d\) B.\(I = nAv_d / e\) C.\(I = n e / Av_d\) D.\(I = v_d / neA\)

Q20

Which of the following describes a device that does not follow a linear relationship between current and voltage?

A.Ohmic conductor B.Copper wire C.Non-ohmic device D.Carbon resistor

Q21

Electrical resistivity is defined as the resistance offered by a conductor of:

A.Unit length and any area B.Unit area and any length C.Unit length and unit area of cross section D.Infinite length and zero area

Q22

If a carbon resistor has color bands Green, Blue, Orange, and Gold, what is its resistance value?

A.\(56 \Omega \pm 5\%\) B.\(5.6 k\Omega \pm 10\%\) C.\(56 k\Omega \pm 5\%\) D.\(560 k\Omega \pm 20\%\)

Q23

Three resistors of \(R_1\), \(R_2\), and \(R_3\) are connected in parallel. The equivalent resistance \(R_P\) is given by:

A.\(R_P = R_1 + R_2 + R_3\) B.\(1/R_P = 1/R_1 + 1/R_2 + 1/R_3\) C.\(R_P = (R_1 R_2 R_3) / (R_1 + R_2 + R_3)\) D.\(R_P = \sqrt{R_1^2 + R_2^2 + R_3^2}\)

Q24

An ideal battery is defined as a source of electromotive force (emf) that has:

A.Infinite internal resistance B.Zero internal resistance C.Internal resistance equal to load resistance D.Varying emf with current

Q25

Kirchhoff's Current Rule (First Rule) states that the algebraic sum of currents at any junction in a circuit is:

A.Infinite B.Equal to the source voltage C.Zero D.Equal to the total resistance

Q26

In a Wheatstone's bridge, the bridge is said to be balanced when the current through the galvanometer is:

A.Maximum B.Zero C.Equal to the source current D.Half of the source current

Q27

A meter bridge is primarily used to measure:

A.Unknown electromotive force B.Unknown resistance C.Specific heat of wire D.Internal resistance of a cell

Q28

The principle of a potentiometer states that the potential difference across any length of a wire of uniform cross-section is:

A.Inversely proportional to its length B.Directly proportional to its length C.Constant regardless of length D.Equal to the internal resistance

Q29

According to Joule's law of heating, the heat produced (\(H\)) in a resistor is proportional to:

A.The current (\(I\)) B.The square of the current (\(I^2\)) C.The inverse of resistance (\(1/R\)) D.The square root of time (\(\sqrt{t}\))

Q30

The phenomenon in which an electric current is produced in a circuit of two dissimilar metals by maintaining their junctions at different temperatures is:

A.Peltier effect B.Seebeck effect C.Thomson effect D.Joule effect

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About this Current Electricity test

This free online practice test covers Current Electricity from the 12th Standard Physics (Samacheer Kalvi) syllabus. Choose the number of questions and an optional time limit, then answer and submit — everything is checked in your browser, with the correct answers and a worked explanation shown at the end. For the full solutions to every question in this set, see the solved MCQs page.

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