Multiple Choice A2

Mean power = Mean (RMS) voltage x Mean (RMS) current

The I0 is the peak current so multiply by root 2

D

D when theta is 0, cos(0) = 1 and this means coil is parallel so max emf induced therefore max current.

1. Because they’re induced when the B field changes direction

   The induction I is proportional to the rate of change of the B field

   So it’s related to the rate of change not the direction itself

D

C (NOT ALL ON A STRAIGHT LINE) - implies not obeying inverse square law)

D

C (its what you would observe - A you can see due to the random motion of the smoke particles)

300kPa ABOVE atmospheric pressure, so the change is 200kPA

C

B (SPEED DOESN’T CHANGE!!!)

C (SCALARS DO NOT CANCEL EACHOTHER OUT!)

D

A

D (C decreases, and since still connected to battery, V is constant so Q must decrease. Since E = 1/2Qv, E must also decrease!)

A

D

B

C

C

C

A (Use the fields equations and set them equal to eachother)

A

B

B

B (Weight is just F!!!!!!!!!)

B

D

D

Also the fact that capacitor stores only 50 percent of total energy transferred by the battery

C (no force acting since Bqvsin theta where sin theta is 180 degrees which is 0! - they are not acting perpendicular!)

assume its x² and then the derivative is 2x so a straight line!

Incredible question!

Must convert to kelvin, then re arrange to get equation of straight line! (D))

B

C

To reduce the effect of heat transfer between the block and the surroundings, you want the temperature of the surroundings (TS) to be as close as possible to the average temperature of the block during the heating process.

B

Vertically downwards

B

Grav potential gets more negative the closer out you are, so the greatest differnce will be the furthest and smallest (A)

D

checkkkkkk (a)

B

A (Mass on spring NOT pendulum!!!)

D FREQUENCY NOT TIME PERIOD!

Read carefully!!! Grav field strength (A)

CONSTANT VELOCITY - so when magnetic force = electric force

A

C

A (Temperature is in K)

A ???? Vx = 2Vy so sub 2Vy into Vx

D, in these questions involving DIAMETERS, use radius to get final expression, and then just sub in d/2 into equation.

B) continue to generate energy and are cooled by the water.

AExplanation: Used fuel rods still emit a significant amount of radiation (including beta and gamma radiation) and continue to generate heat for a period of time after they are removed from the reactor. The water in which they are stored helps to cool the rods and absorb the heat, preventing them from becoming too hot or dangerous to handle. The cooling process is essential for safety.

A

B (Control rods: Boron and Cadmium, Moderator: (Heavy) water, graphite)

Initially, flux linkage is 0 (since cos90 where theta is the angle between the normal of the coil and the field lines). Then rotated about 40 degrees, meaning angle now between the normal and the field lines is 50 degrees!!! The just use BANcostheta (C)

A

A (since the battery is remaining connected, the voltage wont change since there is only a capacitor in this circuit!)

If the battery was not connected, the charge would stay the same (since it has nowhere else to flow, and since the capacitance still increases, then the voltage must decrease

D (DRAW THE FIELD LINES! S is being balanced by the other 4, so when it is removed, the other 4 charges are going to move in the direction that S was opposing (so will move from X to S)

1 orbit is 24 hours!!!! NOT 365 days! (B)

C (Might be moving at 90 degrees to field lines but still going to be falling in the direction of them!)

NOT MAGNETIC FIELDS SO CANT USE FLHR!!! (D) - Remember electric field is the direction that the force will act (like gravitational) and since its an electron here, its going to be opposite to what a positive charge would!)

D

B

D

D

C

C (Doesn’t say anything about time!)

Force exerted outwards in all directions so C

C

Q10

Circular, curving upwards, since it says “The magnetic field is horizontal and at right angles to v.” so using FLHR, it is upwards. Circular since The force is always perpendicular to the velocity

• So it never speeds up or slows down the particle — just redirects it (A)

Q9) A

its going from 0-> small, and then from max -> 0 so from max → 0 will have largest change. - THIS WOULD APPLY IF IT WERE A VOLTMETER!!!

D (Since the gradient of EMF is the gradient of the magnetic flux)

AVERAGE EMF ACROSS 0 - t2 so its just (Ntheta - 0/t2) (B)

C Since efficiency can be calculated using output power/ input power x 100

B

C

Wording!!!! Percentage transferred FROM! (so its 100- 14 = 86) (D)

A = Reduce NOT eliminate

B = Eddy currents oppose flux changes, and cause energy loss and heating, but they don’t directly reduce the magnetic field strength generated by the coil. They mainly make the system less efficient and slightly resist fast changes in flux.

C) They increase if the peak current in the secondary coil increases.

✅ Correct!

• More current in the secondary → greater changing magnetic field → greater change in flux

• This induces larger eddy currents in the core.

D) They circulate around the core in the direction of the magnetic field.

🔸 Incorrect.

• Eddy currents are perpendicular to the changing magnetic field — they circulate in planes at right angles to the magnetic field lines, not along them. (Lenz’s law - perpendicular

Max velocity = equilibrium position

Min velocity = Amplitude

B

C (The RMS current is the value of an AC current that would produce the same heating effect (i.e. same power dissipation) as a DC current.)

4.1) Since electron, force acts opposite to direction of electric field (since that is the direction a positive charge would feel). So if force acting towards R, then the field must be acting downwards (towards S)

4.2) Its electron again, so the direction will be opposite! FLHR!

B Must find V in terms of g and l and then form equation of tenstion: T -mg = mv²/r and sub v into to find t = 3mg

B (Remember electric field strength = VECTOR and electric potential = SCALAR!)

E = 1/2kA² (derived from E= 1/2k(e²) where e is extension! D

A (shoudl end up with 0.375 × 9.81

Answer A

The emfs induced on opposite sides of the coil cancel each other out. EMF only induced when entering and leaving field - not when entire area inside it.

D

B

D

D (T² = R³) - and common sense!

D (Total energy = -GMm/2r)