Electricity

Question 1

EMF

Answer 1

The energy provided per coulomb of charge as it passes through the cell

Question 2

Electron flow

Answer 2

Electrons are attracted to the positive end and are moved towards the opposite end of the cells and therefore this side stays positive.
Electrons are repelled by the negative end and the chemical reactions place more electrons at the negative and it stays negative.

Therefore the electron moves clockwise.

Question 3

Potential difference

Answer 3

The work done per unit of charge

Question 4

Current

Answer 4

Rate of flow of charge

Question 5

Ohm’s Law

Answer 5

1. Current through a conductor is directly proportional to the potential difference across the conductor at a constant temp.
2. Relationship I and V

Question 6

Resistance

Answer 6

1. A material’s opposition to the flow of charge
2. The electron’s kinetic energy -> heat energy

Question 7

Ohmic Conductors V.s Non-Ohmic Conductors

Answer 7

1. Graph: gradient=resistance (R= i/v :. 1/r= v/i)
2. Ohmic= origin, straight line :. Resistance does not vary with current (if low, current x res.)
3. Non-Ohmic= origin, straight at first, then shoots= increasing res

Question 8

Factors that affect resistance

Answer 8

LMTT
1. Length: long x res
2. Material: nickel, tungsteen x res
3. Thickness: Thin x res.
4. Temp: high temp x res

Question 9

What is the amount of energy dissipated in the resistor?

Answer 9

The amount of energy dissipated in the resistor equals to the work done in moving the electric charge between the ends of a resistor

Question 10

Potential difference

Answer 10

The amount of work doe per coulomb of charge moved between two points in a circuit

Question 11

Fuse

Answer 11

1. To protect appliances from damage due to high current
2. It will melt and open the circuit

Question 12

Power

Answer 12

The rate at which electrical energy is converted to other forms of energy in an electrical circuit.
W=j.s^-1

Question 13

If 2 bulbs are connected to a 240V Battery , one 100W and other 60W,
Which is brighter?

Answer 13

100W bulb will be brighter as according to P=I.V
The 100W bulb will have less resistance as it would have higher current and therefore current x brightness

Question 14

Cost of Electricity

Answer 14

Power rating of appliance (kwh). T(hrs).price of kwh

Question 15

Convectional current

Answer 15

The rate of flow of positive charge from the positive terminal of the cell to the negative terminal

Question 16

Magnetic field

Answer 16

A region in space in which a magnetic object experiences a force