Level 1 — RecognitionElectricity & Charge Basics

Electricity & Charge Basics

⏱ 20 minutes30 marksprintable — key stays hidden on paper

Chapter: 1.1 Electricity & Charge Basics Level: 1 — Recognition Time Limit: 20 minutes Total Marks: 30

Section A — Multiple Choice (1 mark each)

Choose the single best answer.

Q1. The SI unit of electric charge is the: (a) volt (b) ampere (c) coulomb (d) ohm

Q2. Which particle carries a negative charge? (a) proton (b) neutron (c) electron (d) photon

Q3. Ohm's Law is correctly stated as: (a) $V = I/R$ (b) $V = IR$ (c) $I = VR$ (d) $R = VI$

Q4. The unit of current, the ampere, is equivalent to: (a) one joule per second (b) one coulomb per second (c) one volt per ohm-second (d) one watt per volt

Q5. Which of the following is the best electrical insulator? (a) copper (b) silicon (c) rubber (d) aluminium

Q6. A resistor of $10\,\Omega$ carries a current of $2\,\text{A}$ . The voltage across it is: (a) $5\,\text{V}$ (b) $12\,\text{V}$ (c) $20\,\text{V}$ (d) $0.2\,\text{V}$

Q7. Electrical power is given by all of the following EXCEPT: (a) $P = VI$ (b) $P = I^2R$ (c) $P = V^2/R$ (d) $P = V/I$

Q8. Conventional current is defined as the direction of flow of: (a) positive charge (b) electrons (c) neutrons (d) magnetic flux

Q9. The unit of capacitance is the: (a) henry (b) farad (c) tesla (d) weber

Q10. Which quantity is measured in joules? (a) power (b) energy (c) charge (d) potential difference

Section B — Matching (1 mark each, 8 marks)

Q11. Match each quantity in Column X to its unit in Column Y. Write the letter.

Column X	Column Y
(i) Voltage	A. henry
(ii) Resistance	B. ampere
(iii) Inductance	C. volt
(iv) Current	D. ohm

Q12. Match each schematic symbol/component to its role. Write the letter.

Component	Role
(i) Battery	A. stores energy in an electric field
(ii) Resistor	B. provides a steady DC source
(iii) Capacitor	C. stores energy in a magnetic field
(iv) Inductor	D. opposes/limits current flow

Section C — True/False WITH Justification (2 marks each, 12 marks)

State True or False (1 mark) and give a one-line justification (1 mark).

Q13. A DC signal reverses its direction periodically, whereas an AC signal is constant.

Q14. In a metallic conductor, electrons physically flow in the direction opposite to conventional current.

Q15. One volt equals one joule of energy transferred per coulomb of charge.

Q16. A semiconductor's conductivity lies between that of a conductor and an insulator.

Q17. Doubling the current through a fixed resistor doubles the power it dissipates.

Q18. Electric field strength points from regions of low potential to high potential.

Answer keyMark scheme & solutions

Section A (10 marks)

Q1. (c) coulomb — the coulomb (C) is the SI unit of charge. (1)

Q2. (c) electron — charge $-1.602\times10^{-19}\,\text{C}$ . (1)

Q3. (b) $V = IR$ — voltage equals current times resistance. (1)

Q4. (b) one coulomb per second — $1\,\text{A} = 1\,\text{C/s}$ , current is rate of charge flow. (1)

Q5. (c) rubber — non-metal with no free charge carriers; copper/aluminium are conductors, silicon a semiconductor. (1)

Q6. (c) $20\,\text{V}$ — $V = IR = 2 \times 10 = 20\,\text{V}$ . (1)

Q7. (d) $P = V/I$ — incorrect; the valid forms are $VI$ , $I^2R$ , $V^2/R$ . (1)

Q8. (a) positive charge — conventional current flows from + to −. (1)

Q9. (b) farad — capacitance unit, $1\,\text{F} = 1\,\text{C/V}$ . (1)

Q10. (b) energy — joule is the unit of energy; power is watts. (1)

Section B (8 marks)

Q11. (i)→C, (ii)→D, (iii)→A, (iv)→B. (1 each = 4)

Q12. (i)→B, (ii)→D, (iii)→A, (iv)→C. (1 each = 4)

Section C (12 marks)

Q13. False. (1) AC (not DC) periodically reverses direction; DC flows in one constant direction. (1)

Q14. True. (1) Electrons are negative, so they drift opposite to the defined positive (conventional) current direction. (1)

Q15. True. (1) By definition $1\,\text{V} = 1\,\text{J/C}$ — energy per unit charge. (1)

Q16. True. (1) Semiconductors (e.g. silicon) have conductivity between conductors and insulators and can be doped. (1)

Q17. False. (1) $P = I^2R$ , so doubling $I$ gives $(2I)^2R = 4I^2R$ — power quadruples, not doubles. (1)

Q18. False. (1) The electric field points from high potential to low potential (direction a positive charge is pushed). (1)

[
  {"claim":"Q6: V=IR gives 20V for I=2A,R=10ohm","code":"I=2; R=10; V=I*R; result = (V==20)"},
  {"claim":"Q17: doubling current quadruples power in fixed resistor","code":"I,R=symbols('I R',positive=True); P1=I**2*R; P2=(2*I)**2*R; result = (simplify(P2/P1)==4)"},
  {"claim":"Q15: 1V = 1J/C dimensionally consistent (1J over 1C = 1V)","code":"J=1; C=1; V=J/C; result = (V==1)"},
  {"claim":"Q4: 1A equals 1C per 1s","code":"Q=1; t=1; I=Q/t; result = (I==1)"}
]