Electricity

Topics in this chapter

• Electric Charge, Current And Voltage
• Ohm's Law And Resistance
• Resistivity And Resistance Factors
• Series And Parallel Circuits
• Heating Effect And Electric Power
• Domestic Electric Circuits

Cheat sheet

Practice questions

1. Question 1Q-76F59F

   Which of the following units is equivalent to the SI unit of electrical resistance, the ohm?

   1. A.Volt \times \text{ampere}
   2. B.Volt / \text{ampere}
   3. C.Ampere / \text{volt}
   4. D.Joule \times \text{coulomb}
   See the answer and solution
2. Question 2Q-A64C97

   A wire of resistance $R$ is stretched until its length is doubled while its volume remains constant. What is the new resistance of the wire?

   1. A.2R
   2. B.4R
   3. C.R / 2
   4. D.R / 4
   See the answer and solution
3. Question 3Q-70416B

   Why are copper and aluminium usually employed for electricity transmission lines instead of iron?

   See the answer and solution
4. Question 4Q-FBC4B1

   Three resistors of resistances $2\ \Omega$, $3\ \Omega$, and $6\ \Omega$ are connected in parallel. What is the equivalent resistance of the combination?

   1. A.11 \Omega
   2. B.1 \Omega
   3. C.6 \Omega
   4. D.0.5 \Omega
   See the answer and solution
5. Question 5Q-CE4256

   An electric bulb is rated $220\text{ V}$ and $100\text{ W}$. When it is operated on $110\text{ V}$, what is the power consumed by the bulb?

   1. A.100 W
   2. B.50 W
   3. C.25 W
   4. D.200 W
   See the answer and solution