Required Practicals

Question 1

RP1
What piece of apparatus can be used to generate a wave in string?

Answer 1

Vibration generator driven by a signal generator

Question 2

RP1
Why should the signal generator be left for 20 minutes before use?

Answer 2

To stabilise frequency

Question 3

RP1
Safety measures for stationary wave on string

Answer 3

Stand could topple and injure, use counterweight

Question 4

RP1
How can tension in a string be varied?

Answer 4

Change masses hanging from pulley

Question 5

RP1
How can uncertainty be reduced to do with length of string?

Answer 5

Longer string, lower uncertainty

Question 6

RP1
Equation for wave speed, mass per unit length and tension in string

Answer 6

C = √(T/m)

Question 7

RP1
When plotting L against T, how can you work out wave speed?

Answer 7

2 times gradient

Question 8

RP2
What safety precautions should be taken when operating a laser?

Answer 8

Never look directly at the bean
Ensure no reflective surfaces
Display a warning sign ⚠️

Question 9

RP2
How should you measure the fringe spacing of an interference pattern?

Answer 9

Measure across 11 fringes for 10 fringe spacings
Reduced uncertainty

Question 10

RP2
Equation for double slit:
Wavelength=?

Answer 10

Wavelength= (w×s)/D

Question 11

RP2
How do you work out wavelength?

Answer 11

Plot w against D
Gradient × s is wavelength

Question 12

RP2
Describe interference pattern if white light used instead of monochromatic

Answer 12

Central white fringe. Other fringes: spectra blue light closest to centre, red furthest from centre

Question 13

RP3
What is g?

Answer 13

Gravitational field strength
g=9.81 on earth

Question 14

RP3
What is free fall?

Answer 14

Only force acting on an object is gravity

Question 15

RP3
What graph can be plotted to determine g?

Answer 15

2s/t against t
Gradient is g

Question 16

RP3
How should you reduce air resistance?

Answer 16

Use a small ball bearing

Question 17

RP5
State equation used to calculate resistivity of a wire

Answer 17

P=(RA)/L

Question 18

RP5
What is the unit of resistivity?

Answer 18

Ohm meters

Question 19

RP5
How does the resistance of a wire change when the length is decreased?

Answer 19

Length of wire decreases, resistance decreases

Question 20

RP5
How does the resistance of a wire change when the cross sectional area is decreased?

Answer 20

Area decreases, resistance increases

Question 21

RP5
Why should the power supply be switched off between readings?

Answer 21

Temperature of wire should remain constant so turning off will stop wire heating too much

Question 22

RP5
How should resistivity be calculated using a graph?

Answer 22

Plot R against L
Gradient=R/L
Resistivity= gradient × A