Physics MCQ Assessment

Both blocks are moving together, and the string is inextensible, so they have common acceleration, a

For Block B,

F =ma

T = 4a

For Block A,

F = ma

12 - T = 2a

24- 2T = 4a

Solving simultaneously,

24 -2T =T

3T =  24

T = 8 N

heat supplied in 5 min = 300 x 5 x 60 = 90000J

Q = mc T

90000=3 x c x 75

c = 400 J/Kg K

As the boy is climbing at constant speed, there should be no change to his kinetic store.

Therefore, the change is mainly from chemical potential in his body to gravitational potential.

Pressure of gas in mercury barometer= hpg = 6 x 13600 x10 units

pressure of gas in water barometer= h x 1000 x 10

Therefore,

6 x 13600 x10 = h x 1000 x 10

h = 13.6 x 6 = 81.6 = 82cm ( 2sf)

Recall that as water waves move through deep or shallow regions, only frequency remains unchanged.

Use the wave equation.

velocity = frequemcy x wavelength

frequency = 18/3.6 = 5Hz

5  = 15/w

w = 15/5 = 3 cm

When an object is placed at a distance of twice the focal length (2F) from a convex lens, the image formed is located at the same distance (2F) on the opposite side of the lens. This image is real, inverted (upside down), and the same size as the object. 

total mass = 1500 + 1100 =2600Kg

F = ma

F = 2600(1.3)

= 3380N

Ultraviolet rays are used in sunbeds for artificial sun tanning.

Microwaves are used in satellite communications.

Gamma radiation can damage human proteins and DNA.

UV are used to check for counterfeit notes.

Draw your velocity-time graph. Find the area under the graph.

0.5 x 1.5 x12 = 9 m/s

Need to use graphical method to solve.

Sketch velocity-time graph. the gradient represents the acceleration which is 10.

let the time taken to fall to the ground be t. therefore the final velocity before it hit the ground would be 10t.

the area under the graph

0.5 x t x 10t = 125

5t2 = 125

t = 5 sec

velocity = frequency x wavelength

4.0 × 10^5 = f x 5.0 × 10^6

f = 0.08 Hz

period = 1/0.08 = 12.5 s

all the negatives charges(electrons will move towards the X as it is closer to the positive charged rod)

This will result in the above charge distribution.

In a distance-time graph, the speed is represented by the gradient of the graph. Thus, the gradient should be positive and constant initially and then become less steep after seeing the traffic light.

alpha is positive and can be stopped by paper

beta is negative and can be stopped by a few cm of aluminium

gamma has no charge and can only be partially stopped by several cm of lead.

The graph becomes flat after a while which means distance no longer increase. So it comes to a stop

1 . A 5A fuse should be used inside the heater. Wrong. operating current is 6A. Fuse should be slightly above 6A

2 . The fuse should be placed on the brown wire of the cable. Correct. Fuse should be on live wire which is brown.

3 . The neutral wire should be connected to the metal case of the heater.Wrong. The Earth Wire should be connected to the metal case not the neutral wire

use right hand grip rule to find the polarity of both electromagnets.

There will be a south pole to the left of the compass and a north pole to the right of the compass.

The magnetic field line will be from right to left, so the compass will point to the left

Alpha particles has high ionising power but low penetration

Dark colours are good radiator and absorber of heat while lighter and shiny colours are bad radiator and absorber of heat.

Since we want the temperature of the cold plate to increase most slowly, hot plate should radiate heat slower (shiny) and cold plate should absorb heat slower( shiny)

black is a good radiator and absorber of radiation.

Outer surface needs to absorb heat fast(black) while the inner surface needs to retain heat(shiny)

By  Law of reflection, the angle of incidence = angle of reflection.

Also, distance of the object from the mirror = distance of the image behind the mirror

total effective resistance = 3 + 1.5 = 4.5 ohms

Total current = 9/4.5 = 2A

current through R2 = 2/1 = 1A

Power = IV = 1^2 x 3 = 3W

right hand grip rule

Water waves are transverse so particles will only move up and down if the wave is moving left to right.

Draw another wave to the right and you can see that Z will move up

XY represents the amplitude

When the coil rotates faster, both the induced voltage (amplitude) and frequency will increase

As air is sucked out, the number of air molecules in the packet decreases. Thus, there will lesser collision with the inner surface area of the packet drink, leading to a reduction in pressure. Since the outside pressure is greater, the packet shrinks inwards.

In an ideal transformer, power is conserved.

power in the primary coil = 240 x0.15 =36W

Therefore the current and voltage in the secondary coil must give 36W in power.

Only B and C qualify but since this is a stepdown transformer, the secondary voltage must be lower than the primary voltage.

Thus B is the answer

The current passing through component in series would be the same

from O to P, velocity is positive and rising at a decreasing rate. This means acceleration is also positive and decreasing

P to Q: velocity is constant, acceleration is zero

Q to R: steep decrease in velocity (due to parachute being opened) Accleration is now upward and therefore negative. The magnitude is large as the gradient is steep.

R to S: constant velocity, zero acceleration

Use P = IV

1500 = I (240)

I = 6.25 A

During normal operation, neutral wire = 0V, earth wire = 0V

therefore pd = 0V

fusion --> combine to become bigger

fission --> break up to form two or more smaller

Both type of nuclear reactions give out energy

6/3 + 6/6 +6/3 = 5 ohms

20% --> 0.8W

100% --> 4 W

In cold places, heat will be lost to the surrounding so efforts would be made to minimise heat transfer.

The cold sink is deliberately dugged deeper so that it will be lower and cold air cannot circulate in the enclosed space within the igloo

in order from increasing frequency and decreasing wavelength,

radio, micro, infrared, visible, UV, X ray and gamma

Calculating work done using F xd

A) 10 x 1 = 10J

B) 4 x 1 = 4J

C) 20 x 2 = 40J

D) 2 x 2 = 4J

If the box is moving with constant speed, it means the acceleration is zero.

Therefore resultant force is zero.

This could be because the friction between the box and the floor is 30N.

distance travelled from t=15 to t=20

= 5 x 10 = 50m

Distance travelled from t=20 to t=30

= 0.5 x (10+20) x 10 = 150m

total distance travelled for last 15s = 50+150 = 200m

average speed = 200/15 = 13.333 = 13.3m/s (3 sf)

As the parachute is opened, the extra surface area provided by the parachute greatly increases the air resistance, which is directed upwards. At this moment, Air resistance is greater than weight which is directed downwards.

Resultant force = Weight - air resistance

Thus resultant force becomes negative ( or directed upwards)

And acceleration is also negative(upward)

However at this moment, velocity is positive(downward)

Thus, the velocity will decrease. As the velocity decreases, air resistance will also decrease and the resultant force will decrease in magnitude (still negative though)

The convection cycle set up in the water will not reach the bottom, as hot water is less dense and will only rise. Thus, heat transfer to the ice is primarily through conduction via the water. The experiment shows that water is a poor conductor of heat