Incorrect Past Papers

Question 1

Explain how stationary waves are produced

Answer 1

The incident and reflected waves interfere

Question 2

How can measuring 14 half wavelengths be better than measuring just 2 adjacent fringe separations

Answer 2

Measuring multiple fringe separations Reduces uncertainty in d

Question 3

Explain quantum tunnelling

Answer 3

A quantum particle can exist in a position where in classical physics, its has insufficient energy to occupy

Question 4

Units for momentum

Answer 4

Kgms^-1

Question 5

State whether the energy required to move point P via path A will be more or less or equal to the nergry required to mngr to P by path B

P. <——
^. Oo. |
A| O. O |B
|. Oo. |
Probe ——

Answer 5

Equal since the energy required to move two points in a gravitational field is independent of path taken

Question 6

As probe from earth travels further away the clock’s desynchronisation. Will they run faster or slower

Answer 6

Faster
The will have a weaker gravitational field

Question 7

State what is meant by a gravitational potential of -1.7*10^9 Jkg^-1

Answer 7

1.7*10^9 joules of energy transferred in moving unit mass from infinity to that point

Question 8

Explain why the diameter of the sun will increase as it become a red giant

Answer 8

The thermal pressure inside the sun with exceed the gravitational forces

Question 9

why can larger particles like muons can be regarded as particle

Answer 9

The de broglie wavelength is to small for interference or diffraction to be seen

Question 10

Explain why alpha particles travel through magnetic field of earth follow a helical path

Answer 10

They have a velocity perpendicular to the field that has a circular motion

They have a velocity parallel to the field that has a linear motion

Question 11

High altitude large cosmic ray observatory which is close to the South Pole. Why is this location good

Answer 11

High up so it’s closer to cosmic rays and reduces interaction with atmosphere

At a location where earth has a stronger magnetic field

Question 12

Why does a dc ammeter will display a greater current than a AC current

Answer 12

AC current will generate reactance in the inductor

Question 13

What’s the units for phase difference

Answer 13

Rad

Question 14

A student looks at a lamp through a filter, the student rotates the filter 90°. What effect does it have on the observed brightness

Answer 14

No effect since a lamp light is unpolarised

Question 15

Student uses glasses to watch a 3D movie, they contain two polarising filters, one for each eye. EXPLAIN HOW THIS ARRANGEMENT ENABLES A DIFFERENT IMAGE TO BE SEEN BY EACH EYE

Answer 15

Only one projected image to pass through to each eye

Question 16

There are two projectors, showing two different images each one with a polarizing filter. A student looks through one filter of his glasses and rotates it 90°. Explain why he does not observe any change in brightness

Answer 16

The image from one projector will decrease while the other project increases in brightness

Question 17

When finding the luminosity of a star, what assumptions do you make of it

Answer 17

It’s a black body

Question 18

What happens to the radius of the sun when it will turn into a red giant

Answer 18

Radius increases due to thermal pressure is greater than gravitational forces

The radius then stops increasing as thermal pressure and yea force balance

Question 19

Considering a magnetic field around the In the inductor, explain why the back emf produced is large enough to allow a lamp to flash

Answer 19

Rapid change in current

Question 20

Explain how back emf is produced

Answer 20

Changing current produces a change in magnetic field which induces a back emf in the conductor

Question 21

Why should a value for a constant be taken from a graph

Answer 21

Range of values

Question 22

What type of light does rainbow have

Answer 22

Plane polarised

Question 23

Why does the brightness decrease from the ends of a rainbow to the highest point

Answer 23

A rainbow has plane polarised light

There’s a gradual decrease as the rainbow goes from vertical to horizontal

Question 24

What’s the phase change in radians from a low dense medium to high dense medium

Answer 24

Pi