Physics 2a Topics 1, 2 & 3

Question 1

Explain why a negatively charged comb is able to pick up little pieces of uncharged paper.

Answer 1

Is is because the negatively charged comb repels electrons in paper, which causes induction of a positive charge on the surface of the paper

Question 2

Describe how electrostatic paint sprayers use static electricity to get an even coat of paint.

Answer 2

Each paint drop repels all the other, since they’ve all got the same charge and the object to be painted is given an opposite charge to the gun, this attracts the fine spray of paint

Question 3

Give the definition for current.

Answer 3

Current is the rate of flow of charge

Question 4

What type of current do cells and batteries supply?

Answer 4

Direct current (d.c)

Question 5

In a circuit, what happens if you increase:

a) potential difference?
b) resistance?

Answer 5

a) if you increase the potential difference then more current will flow
b) if you increase the resistance then less current will flow

Question 6

Should a voltmeter be placed in series or in parallel with a component in a circuit?

Answer 6

A voltmeter shall be placed parallel with a component in a circuit.

Question 7

Describe how the resistance of an LDR changes with light intensity.

Answer 7

In bright light, the resistance is low & in darkness the resistance is high

Question 8

Resistors get hot when an electric current passes through them. Give an example of this

Answer 8

They melt and break the circuit if the current gets too high

Question 9

What’s the difference between speed and velocity?

Answer 9

Speed is how fast you’re going-the direction doesn’t matter. Velocity must also have the direction given. The distance travelled in a particular direction is called the displacement.

Question 10

What is acceleration? What is the unit used?

Answer 10

Acceleration is a vector quantity like velocity - it has magnitude and direction (m/s2️⃣)

Question 11

What is “terminal velocity”?

Answer 11

It is maximum speed

Question 12

Explain what a reaction force is and where it pops up.

Answer 12

Reaction force is when an object pushes back against you

Question 13

If an object has zero resultant force on it, can it be moving? Can it be accelerating?

Answer 13

No, yes

Question 14

What causes the build up of static electricity? Which particles move when static builds up?

Answer 14

Friction, Electrons