20 multiple-choice (MCQ / objective) questions from this chapter, in every exam-style shape used in the paper. Every question comes with an explanation along with the answer, so you remember why the option is correct, not just which one it is.
1 Direct Questions
Direct Questions
- 1 markWhat is the SI unit of electric current?
(A) Volt(B) Ampere(C) Ohm(D) Coulomb - 1 markAn ammeter must always be connected in the circuit in:
(A) Parallel(B) Series(C) Either series or parallel(D) None of these - 1 markOf silver, copper, aluminium and iron, the best conductor (lowest resistivity) is:
(A) Iron(B) Aluminium(C) Copper(D) Silver - 1 markAn electric bulb is usually filled with:
(A) Oxygen and hydrogen(B) Nitrogen and argon(C) Carbon dioxide(D) Pure vacuum only - 1 markTwo resistors of 4 Ω and 6 Ω are connected in series. Their equivalent resistance is:
(A) 2.4 Ω(B) 24 Ω(C) 10 Ω(D) 1.5 Ω - 1 markThe heat H produced by a current I flowing through a resistance R for time t is given by:
(A) (B) (C) (D)
2 Assertion-Reason
Assertion-Reason
- 1 markAssertion (A): Ohm’s law is not obeyed if the temperature of the conductor keeps changing. Reason (R): Resistance itself changes with temperature, so no longer stays constant.
(A) Both A and R are true, and R is the correct explanation of A.(B) Both A and R are true, but R is not the correct explanation of A.(C) A is true, but R is false.(D) A is false, but R is true. - 1 markAssertion (A): Alloys like nichrome are preferred over pure metals for electric heating elements. Reason (R): Alloys generally have higher resistivity than their constituent metals and do not oxidise readily at high temperatures.
(A) Both A and R are true, and R is the correct explanation of A.(B) Both A and R are true, but R is not the correct explanation of A.(C) A is true, but R is false.(D) A is false, but R is true.
3 Match the Following
Match the Following
- 1 markMatch the quantity in Column A with its SI unit in Column B.
Column A: 1) Current 2) Potential difference 3) Resistance 4) Power
Column B: a) Volt b) Watt c) Ampere d) Ohm
(A) 1-a, 2-b, 3-c, 4-d(B) 1-c, 2-a, 3-d, 4-b(C) 1-b, 2-c, 3-a, 4-d(D) 1-d, 2-a, 3-b, 4-c - 1 markMatch the device in Column A with its use in Column B.
Column A: 1) Ammeter 2) Voltmeter 3) Rheostat 4) Fuse
Column B: a) Protects a circuit from excess current b) Measures potential difference c) Changes resistance without changing source voltage d) Measures current
(A) 1-a, 2-b, 3-c, 4-d(B) 1-b, 2-d, 3-a, 4-c(C) 1-d, 2-b, 3-c, 4-a(D) 1-d, 2-c, 3-b, 4-a
4 Statement-Based Questions
Statement-Based Questions
- 1 markStatement I: In a series circuit, the current is the same in every part of the circuit. Statement II: In a parallel circuit, the potential difference across each resistor is the same. Choose the correct option:
(A) Both statements are true.(B) Both statements are false.(C) Statement I is true, Statement II is false.(D) Statement I is false, Statement II is true. - 1 markStatement I: A thicker wire of the same material and length has more resistance than a thinner one. Statement II: Resistance is inversely proportional to the area of cross-section. Choose the correct option:
(A) Both statements are true.(B) Both statements are false.(C) Statement I is true, Statement II is false.(D) Statement I is false, Statement II is true.
5 Arrange in the Correct Order
Arrange in the Correct Order
- 1 markArrange these scientists in the order of their birth year, earliest first: (i) Georg Simon Ohm (ii) Andre-Marie Ampere (iii) Alessandro Volta
(A) (i), (ii), (iii)(B) (iii), (ii), (i)(C) (ii), (i), (iii)(D) (iii), (i), (ii) - 1 markArrange the steps of Activity 11.1 (studying Ohm’s law) in the correct order: (i) Calculate V/I for all four pairs of readings (ii) Set up the nichrome-wire circuit with one cell and note the readings (iii) Plot a graph of V against I (iv) Repeat with two, three and then four cells
(A) (ii), (iv), (i), (iii)(B) (i), (ii), (iii), (iv)(C) (iii), (ii), (i), (iv)(D) (iv), (ii), (i), (iii)
6 Fill in the Blanks
Fill in the Blanks
- 1 markA device used to change the resistance in a circuit without changing the source voltage is called a ______.
(A) Fuse(B) Ammeter(C) Rheostat(D) Cell - 1 markIn a ______ combination, the reciprocal of the equivalent resistance equals the sum of the reciprocals of individual resistances.
(A) Series(B) Parallel(C) Mixed(D) Star
7 Odd One Out
Odd One Out
- 1 markWhich one of the following is the odd one out?
(A) Silver(B) Copper(C) Aluminium(D) Rubber
8 Passage-Based Questions
Passage-Based Questions
Passage
A group of students set up Activity 11.1: a 0.5 m nichrome wire XY, an ammeter, a voltmeter, and four cells of 1.5 V each. They first used one cell and noted the ammeter and voltmeter readings, then repeated with two, three and four cells, calculating V/I each time. When they plotted V against I, the graph came out as a straight line passing through the origin.
- 1 markAccording to the passage, what shape does the V-I graph take?
(A) A curve bending upward(B) A straight line through the origin(C) A straight line not through the origin(D) A horizontal line - 1 markAccording to the passage, what quantity was calculated after each reading?
(A) I/V(B) V x I(C) V/I(D) V + I
9 True / False
True / False
- 1 markConsider the statements: (i) An ammeter is connected in series in the circuit. (ii) A voltmeter is connected in parallel across the points between which the potential difference is measured. (iii) An ammeter is connected in parallel across the component whose current is to be measured. Which are true?
(A) (i) and (ii) only(B) (i), (ii) and (iii)(C) (ii) and (iii) only(D) (i) only
Answer Key and Explanations
Direct Questions
- (B) Electric current is measured in ampere (A), named after Andre-Marie Ampere.
- (B) An ammeter is connected in series so the same current flowing through the component also flows through it.
- (D) Table 11.2 gives silver the lowest resistivity, m, of the four.
- (B) Chemically inactive nitrogen and argon gases prolong the filament’s life.
- (C) In series, resistances simply add: .
- (C) Joule’s law of heating: .
Assertion-Reason
- (A) Both A and R are true, and R correctly explains A: resistance itself changes with temperature, so the ratio V/I stops being constant.
- (A) Both true, and R (higher resistivity, resists oxidising) is exactly why alloys suit heating elements.
Match the Following
- (B) Current-ampere, potential difference-volt, resistance-ohm, power-watt.
- (C) Ammeter measures current, voltmeter measures p.d., rheostat varies resistance, fuse protects against excess current.
Statement-Based Questions
- (A) Activity 11.4 confirms the series-current fact; Activity 11.6 confirms the parallel-voltage fact.
- (D) Statement I is false: a thicker wire (larger area) has LESS resistance, exactly because (Statement II, which is true).
Arrange in the Correct Order
- (B) Birth years: Volta 1745, Ampere 1775, Ohm 1787, so Volta, then Ampere, then Ohm.
- (A) As in the book: set up the circuit with one cell and note the readings, repeat with two, three and four cells, calculate V/I for each pair of readings, and then plot the V-I graph. Every other option either starts before the circuit is set up or repeats the readings before taking the first one.
Fill in the Blanks
- (C) A rheostat is exactly this kind of variable-resistance device.
- (B) This reciprocal-sum rule, , is specifically the parallel-combination law.
Odd One Out
- (D) Silver, copper and aluminium are all good conductors; rubber is an insulator.
Passage-Based Questions
- (B) The passage states the plotted V-I graph is a straight line passing through the origin, the signature of Ohm’s law.
- (C) The passage says the students “calculated V/I each time”: this ratio is the resistance.
True / False
- (A) (i) and (ii) are true: the book connects the ammeter in series and the voltmeter in parallel across the two points. (iii) is false, because an ammeter must be in series so that the same current flows through it.
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