Electric current is the rate of flow of charge, measured against the unit of charge called the coulomb, so this IB sheet starts from the definition of current itself. The key records P = VI and that parallel resistance comes out less than the smallest resistor.
Key Takeaways
Electric current is the rate of flow of charge (Q1).
The unit of electric charge is the coulomb (Q2).
Parallel resistance is less than the smallest individual resistance.
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.Electric current is defined as
(a) the rate of flow of charge(b) the flow of voltage(c) the rate of flow of energy(d) the movement of resistance
2.The unit of electric charge is the
(a) coulomb(b) ampere(c) volt(d) ohm
3.Ohm's law states that V =
(a) IR(b) I ÷ R(c) R ÷ I(d) I + R
4.For resistors connected in series, the total resistance is
(a) the sum of the individual resistances(b) less than the smallest resistance(c) always 1 Ω(d) half the largest resistance
5.For resistors connected in parallel, the total resistance is
(a) less than the smallest resistance(b) greater than the largest resistance(c) equal to the sum of the resistances(d) always zero
6.The power dissipated in a resistor is given by
(a) P = VI(b) P = V ÷ I(c) P = I ÷ V(d) P = V + I
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.Define electric current.
8.State Ohm's law.
9.Write the formulas for the total resistance of resistors in series and in parallel.
10.What is the unit of resistance?
11.Write the formula for power dissipated in a resistor.
12.What happens to the current if the resistance is halved at constant voltage?
13.Define potential difference.
14.State the relation between charge, current and time.
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.A current of 3 A flows for 4 s. Using Q = It, find the charge that passes.
16.A 12 V battery is connected to a 4 Ω resistor. Using I = V ÷ R, find the current.
17.Resistors of 2 Ω, 3 Ω and 5 Ω are connected in series across a 20 V supply. Find the total resistance, then using I = V ÷ R find the current.
18.Two 6 Ω resistors are connected in parallel. Using 1/R = 1/R₁ + 1/R₂, find the total resistance.
19.A resistor of 10 Ω carries a current of 2 A. Using P = I²R, find the power dissipated.
20.A charge of 60 C passes a point in a circuit in 20 s. Using I = Q ÷ t, find the current.
Answer Key
1. a) the rate of flow of charge
2. a) coulomb
3. a) IR
4. a) the sum of the individual resistances
5. a) less than the smallest resistance
6. a) P = VI
7. Refer to solution guide.
8. Refer to solution guide.
9. Refer to solution guide.
10. Refer to solution guide.
11. Refer to solution guide.
12. Refer to solution guide.
13. Refer to solution guide.
14. Refer to solution guide.
15. Refer to solution guide.
16. Refer to solution guide.
17. Refer to solution guide.
18. Refer to solution guide.
19. Refer to solution guide.
20. Refer to solution guide.
End of Worksheet
People Also Ask
What is electric current?
The rate of flow of charge, option (a) in this worksheet (Q1).
What is the unit of electric charge?
The coulomb, option (a) in this worksheet (Q2).
How does parallel resistance compare with the smallest resistor?
It is less, from the answer key on this page.
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