Electricity - Graphs, Circuit diagrams and Formulas

Question 1

Describe the Ohms law graph.

Answer 1

A graph with a positive gradient starting from the origin.

The current is on the x axis, the voltage on the y axis and the gradient is the resistance.

Question 2

Describe the following electric circuit symbols -
1. Closed switch
2. Open switch
3. Cell

Answer 2

1. Closed switch → Draw two small circles side by side, then connect them with a straight line in between.
2. Open switch → Draw two small circles side by side, but this time, connect them with a slightly tilted line that doesn’t touch one side.
3. Cell → Draw one short vertical line, then next to it, draw a longer vertical line.

Question 3

Describe the following electric circuit symbols -
1. Battery
2. Resistor
3. Bulb

Answer 3

1. Battery → Draw one cell, then add more sets of short and long vertical lines in a row.
2. Resistor → Draw a straight horizontal line, then add a small rectangle in the middle.
3. Bulb → Draw a circle. Inside the circle, draw a cross.

Question 4

Describe the following electric circuit symbols -
1. Ammeter
2. Voltmeter
3. Variable resistor

Answer 4

1. Ammeter → Draw a circle and write a big ‘A’ inside it. Make sure to mark the positive and negative terminal

2 . Voltmeter → Draw a circle and write a big ‘V’ inside it. Make sure to mark the positive and negative terminal

3. Variable resistor → Draw a normal resistor (a small rectangle in the middle of a horizontal line), then add a diagonal arrow across it.

Question 5

Give me the formula for:
1. Voltage - Normal
2. Voltage - Ohms Law
3. Current
4. Power

Answer 5

1. Voltage - Normal
   V = E/Q
2. Voltage - Ohms Law
   V = IR
3. Current
   I = Q/T
4. Power
   P = IV
   P = I^2R
   P = V^2/R