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AS physics multiple choice help.

1) A body of mass 4 kg falls vertically through the air.
What is the acceleration of the body when the magnitude of the air resistance is 30N?
[1 mark]
A 17.3 m s −2
B 7.7 m s −2
C 2.3 m s −2
D 0.4 m s −2

2) When the temperature of a copper wire increases, its ability to conduct electricity[1 mark]
A remains the same.
B increases.
C decreases.
D remains the same at first and then increases.

3)What is the best estimate for the order of magnitude for the diameter of an atom?[1 mark]
A 10–14 m
B 10–12 m
C 10–11 m
D 10–8 m

4) Which of the following statements about the behaviour of waves is incorrect?[1 mark]
A All waves can be diffracted.
B All waves can be made to undergo superposition.
C All waves can be refracted.
D All waves can be polarised.

5) Two radio transmitters emit waves at a frequency of 1.4 MHz. A stationary wave is set up between the two transmitters due to the superposition of the radio waves. What is the minimum distance between two nodes in the stationary wave?[1 mark]
A 107 m
B 214 m
C 428 m
D 857 m

6) Experiments on which of the following suggested the wave nature of electrons?[1 mark]
A electron diffraction by a crystalline material
B β− decay
C line spectra of atoms
D the photoelectric effect

7) A progressive wave of frequency 150 Hz travels along a stretched string at as peed of 30 m s −1.What is the phase difference between two points that are 50 mm apart on the string?[1 mark]
A zero
B 90°
C 180°
D 360°

8) Which of the following statements about muons is incorrect? [1 mark]
A A muon is a lepton.
B A muon has a greater mass than an electron.
C If a muon and an electron each have the same de Broglie wavelength then they each have the same momentum.
D A muon with the same momentum as an electron has a larger kinetic energy than the electron.

9) In an experiment to demonstrate the photoelectric effect, a charged metal plate is illuminated with light from different sources. The plate loses its charge when an ultraviolet light source is used but not when a red light source is used.What is the reason for this?[1 mark]
A The intensity of the red light is too low.
B The wavelength of the red light is too short.
C The frequency of the red light is too high.
D The energy of red light photons is too small.

10) Which of the following classes of electromagnetic waves will not ionise neutral atoms?[1 mark]
A ultraviolet
B X radiation
C gamma radiation
D microwave

11) A layer of liquid of refractive index 1.6 covers the horizontal flat surface of a glass block of refractive index 1.5. A ray of light strikes the boundary between them at an angle such that it travels along the boundary afterwards. How does the ray strike the boundary?[1 mark]
A it travels in glass at an angle of 70° to the boundary
B it travels in glass at an angle of 20° to the boundary
C it travels in the liquid at an angle of 70° to the boundary
D it travels in the liquid at an angle of 20° to the boundary

12) A stone of mass 0.4 kg is projected horizontally at a speed of 6.0 m s −1 from the top of a wall, 5.0 m above the surrounding ground. When it arrives at the ground its speed is 10 m s −1 .How much energy is lost by the stone in falling through the air?[1 mark]
A 2.4 J
B 6.8 J
C 12.8 J
D 14.4 J

13) The cell in the following circuit has an emf (electromotive force) of 6.0 V and an internal resistance of 3.0 Ω. The resistance of the variable resistor is set to 12 Ω.How much electrical energy is converted into thermal energy within the cell in 1 minute?[1 mark]
A 0.48 J
B 29 J
C 45 J
D 144 J
(edited 7 years ago)
Original post by somilbh
...


Moved this to the Physics forum for you :h:
Reply 2
1) C
F=ma, so you have a force of 30N acting 'up' and a force of mg (the bodies weight) acting down from the body.
The body's weight can be calculated using 4x9.81(gravity)= 39.24N.
If you think as 'up' as positive and 'down' as negative then the Total forces will be 30N+(-39.24N)= -9.24N. Then simply using F=ma, -9.24=4x-a...(-a as it is accelerating downwards)
so -a = -9.24/4 =-2.31 so a = 2.31.
Therefore C is the answer
2) C
- if you have to supercool something to create a superconductor, it makes sense increasing the temperature would reduce it's ability to conduct
3)C
4)D
only transverse waves can be polarised
5) A
wavelength=speed of light in a vacuum/frequency= 3x10^8/1.4x10^6= 214.286.
As its minimum distance, must mean in the first harmonic: so L=1/2 wavelength, 214.286/2= 107.14m, so 107m rounded.
6) A
7) B.....I THINK not 100% sure on this one. wavelength = c/f = 30/150= 0.2m and 50mm = 0.05m, so 0.05/0.2= 0.25, which is 1/4 of a wavelength i.e 90 degrees
8) D KE=1/2mv^2 or half times momentum squared, so, if they have the same momentum they have to have the same KE
9)D, the electrons in the metal cannot absorb enough energy to break free of their bonds.
10)D- the wavelength of microwaves are too large, so therefore their frequency and consequently their energy isn't large enough to excite ionise the neutral atom
11) C to refract along a boundary, the incident ray has to go from a less dense to a more dense medium i.e. from the glass to the liquid (1.5->1.6), the equation to calculate the critical angle is 0c= sin^-1 (n1/n2)= sin ^(1.5/1.6)= 69.6=70 degrees
12) B NOT 100% sure on this one. to calculate the particle's total energy you need to work out it's gravitational potential energy from the top of the wall and add it to the kinetic energy it gains from being thrown so E(total)= GPE+KE=mgh+1/2mv^2= 0.4x9.81x5+1/2x0.4x6^2= 19.62J+7.2J=26.82J. Then, when it is on the ground it has no gravitational potential energy so, its energy on the ground will come purely from the kinetic energy so again it will be KE=1/2mv^2=1/2 x 0.4 x 10^2=20J. So the energy lost will be 26.82-20= 6.82=6.8J
13) D
I= emf/R+r=6/12+3=0.4A . E=power x time= current x voltage(emf as it is within the cell) x time (in seconds)= 0.4 x 6 x 60=144J
(edited 7 years ago)
Original post by somilbh
1) A body of mass 4 kg falls vertically through the air.
What is the acceleration of the body when the magnitude of the air resistance is 30N?
[1 mark]
A 17.3 m s −2
B 7.7 m s −2
C 2.3 m s −2
D 0.4 m s −2

2) When the temperature of a copper wire increases, its ability to conduct electricity[1 mark]
A remains the same.
B increases.
C decreases.
D remains the same at first and then increases.

3)What is the best estimate for the order of magnitude for the diameter of an atom?[1 mark]
A 10–14 m
B 10–12 m
C 10–11 m
D 10–8 m

4) Which of the following statements about the behaviour of waves is incorrect?[1 mark]
A All waves can be diffracted.
B All waves can be made to undergo superposition.
C All waves can be refracted.
D All waves can be polarised.

5) Two radio transmitters emit waves at a frequency of 1.4 MHz. A stationary waveis set up between the two transmitters due to the superposition of the radio waves.What is the minimum distance between two nodes in the stationary wave?[1 mark]
A 107 m
B 214 m
C 428 m
D 857 m

6) Experiments on which of the following suggested the wave nature of electrons?[1 mark]
A electron diffraction by a crystalline material
B β− decay
C line spectra of atoms
D the photoelectric effect

7) A progressive wave of frequency 150 Hz travels along a stretched string at aspeed of 30 m s −1.What is the phase difference between two points that are 50 mm apart on thestring?[1 mark]
A zero
B 90°
C 180°
D 360°


1. use f=ma
2. in terms of resistance what happens when the wire heats up?
3. not sure??????
4. can longitudinal waves(oscillate along the direction of the wave) be polarised?
5. use c=fλ c=f \lambda?????
6. which experiment in quantum phenomena do you remember being showed/learned about?(remember photoelectric effect is particle nature)
7. not sure :/ ....


@uberteknik
what about 3&7 and any other i got wrong??
Reply 4
Original post by thefatone
1. use f=ma
2. in terms of resistance what happens when the wire heats up?
3. not sure??????
4. can longitudinal waves(oscillate along the direction of the wave) be polarised?
5. use c=fλ c=f \lambda?????
6. which experiment in quantum phenomena do you remember being showed/learned about?(remember photoelectric effect is particle nature)
7. not sure :/ ....


@uberteknik
what about 3&7 and any other i got wrong??


can you pls explain about superconductivity?
Reply 5
Original post by MiDuly
1) C
F=ma, so you have a force of 30N acting 'up' and a force of mg (the bodies weight) acting down from the body.
The body's weight can be calculated using 4x9.81(gravity)= 39.24N.
If you think as 'up' as positive and 'down' as negative then the Total forces will be 30N+(-39.24N)= -9.24N. Then simply using F=ma, -9.24=4x-a...(-a as it is accelerating downwards)
so -a = -9.24/4 =-2.31 so a = 2.31.
Therefore C is the answer
2) C
- if you have to supercool something to create a superconductor, it makes sense increasing the temperature would reduce it's ability to conduct
3)C
4)D
only transverse waves can be polarised
5) A
wavelength=speed of light in a vacuum/frequency= 3x10^8/1.4x10^6= 214.286.
As its minimum distance, must mean in the first harmonic: so L=1/2 wavelength, 214.286/2= 107.14m, so 107m rounded.
6) A
7) B.....I THINK not 100% sure on this one. wavelength = c/f = 30/150= 0.2m and 50mm = 0.05m, so 0.05/0.2= 0.25, which is 1/4 of a wavelength i.e 90 degrees
8) D KE=1/2mv^2 or half times momentum squared, so, if they have the same momentum they have to have the same KE
9)D, the electrons in the metal cannot absorb enough energy to break free of their bonds.
10)D- the wavelength of microwaves are too large, so therefore their frequency and consequently their energy isn't large enough to excite ionise the neutral atom
11) C to refract along a boundary, the incident ray has to go from a less dense to a more dense medium i.e. from the glass to the liquid (1.5->1.6), the equation to calculate the critical angle is 0c= sin^-1 (n1/n2)= sin ^(1.5/1.6)= 69.6=70 degrees
12) B NOT 100% sure on this one. to calculate the particle's total energy you need to work out it's gravitational potential energy from the top of the wall and add it to the kinetic energy it gains from being thrown so E(total)= GPE+KE=mgh+1/2mv^2= 0.4x9.81x5+1/2x0.4x6^2= 19.62J+7.2J=26.82J. Then, when it is on the ground it has no gravitational potential energy so, its energy on the ground will come purely from the kinetic energy so again it will be KE=1/2mv^2=1/2 x 0.4 x 10^2=20J. So the energy lost will be 26.82-20= 6.82=6.8J
13) D
I= emf/R+r=6/12+3=0.4A . E=power x time= current x voltage(emf as it is within the cell) x time (in seconds)= 0.4 x 6 x 60=144J

Your comment in Q.2 is not clearly understood. It needs some elaboration.
Reply 6
Original post by djmans
can you pls explain about superconductivity?


Superconductivity is when a material has no resistivity, and therefore no resistance, this is achieved by lowering the temperature of/around the material to below it's critical temperature, which is usually very low and below 10K (-263degrees).The benefits of superconductivity are that a current can be set up in a material WITHOUT a P.d and can continue flowing forever
Reply 7
Original post by MiDuly
Superconductivity is when a material has no resistivity, and therefore no resistance, this is achieved by lowering the temperature of/around the material to below it's critical temperature, which is usually very low and below 10K (-263degrees).The benefits of superconductivity are that a current can be set up in a material WITHOUT a P.d and can continue flowing forever


thanks, but i have never found a superconductivity question in past papers
Im 99.99% sure B is 7
Reply 9
Original post by MHD30
Im 99.99% sure B is 7
do you mean 7 is B?...
Original post by MiDuly
do you mean 7 is B?...

yes lol
Reply 11
Original post by MHD30
yes lol


Yeah I'm pretty sure it is too aha
Original post by thefatone
1. use f=ma
2. in terms of resistance what happens when the wire heats up?
3. not sure??????
4. can longitudinal waves(oscillate along the direction of the wave) be polarised?
5. use c=fλ c=f \lambda?????
6. which experiment in quantum phenomena do you remember being showed/learned about?(remember photoelectric effect is particle nature)
7. not sure :/ ....


@uberteknik
what about 3&7 and any other i got wrong??


1) C. Yes. Use f=ma to calculate the retardation of gravitational acceleration caused by the air resistance. 9.81 - 30/4 = 2.31m/s actual acceleration.

2) C. Copper has a positive resistance thermal coefficient. i.e. resistance increases with temperature. Hence it's ability to conduct current must fall.

3) C. Hydrogen atom: 10-9 > atom < 10-12 (Answer C fits these limits)

4) D. Transverse waves can be polarised. Longitudinal waves cannot.

5) A. λ=cf=300x1061.4x106=214m\lambda = \frac{c}{f} = \rm \frac{300x10^{6}}{1.4x10^6} = 214m Cancellation requires 180o phase shift = λ2=2142=107m\frac{\lambda}{2} = \frac{214}{2} = 107m

6) A. Diffraction experiments by Young (slits experiment)

7) B. λ=vf=30150=200mm\lambda = \rm \frac{v}{f} = \frac{30}{150} = 200mm. Converting to phase angles ϕ=±50200 x 360=±90o\phi = \rm \pm \frac{50}{200} \ x\ 360 = \pm 90^{o}
A light beam on air with wavelength of 50mm, frequency of 6.0×10^4 and speed is 3.0×10^8 goes into glass which has an index of refraction of 1.5 what are the wavelength, frequency, and speed.
that's what i thought for 13 as well but in the mark scheme it says it's B 29J.
Original post by talltomhall
that's what i thought for 13 as well but in the mark scheme it says it's B 29J.

The question says 'in the following circuit' but there is no circuit. Without that the answer could be anything you want.
However assuming it is a simple series circuit with no other components...
... the poster of that solution has made a mistake and forgotten to square the current in the formula for power = I2R
The correct answer is B, 29J

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