# Physics (2017) | Study Mode

Question 1
A

a = v2 - u$$\frac{2}{2}$$

B

v2 = u2 + 2as

C

s = $$\frac{1}{2}$$ut + at2

D

v2 - u2= 2as

##### Explanation

s = $$\frac{1}{2}$$ut + at2 is a wrong equation, it should be s = $$\frac{1}{2}$$ut + at2

Question 2
A
x - ray
B
C
sunlight
D
sound waves
##### Explanation
Electromagnetic waves do not require any material medium, but sound waves is a mechanical wave that require a material medium

Question 3
A
18.57NC$$^{-1}$$
B
53.06N C$$^{-1}$$
C
2.28NC$$^{-1}$$
D
0.80NC$$^{-1}$$
##### Explanation
Electric Field Intensity (E) = $$\frac{v}{d}$$

= $$\frac{\text{potential difference}}{\text{distance}}$$

= $$\frac{6.5v}{35cm}$$

= $$\frac{6.5}{35 \times 10^{- 2}}$$

= 18.57NC$$^{-1}$$

Question 4
A
To prevent resonance on the bridge
B
To set the bridge into resonance
C
To make the b ridge collapse
D
To spread their weight evenly on the bridge
##### Explanation
Soldiers march disorderly while crossing a bridge to prevent resonance because when soldiers march in orderly manner across a bridge, they generate a rhythmic oscillation of wave out. The bridge and at a certain point, would start oscillation to the same rhym as that of the marching steps. This oscillation would reach a maximum peak when the bridge can no longer sustain its own strength and hence collapses. So for this reasons, soldier are ordered to march disorderly while crossing a bridge

Question 5
A

0.8N

B

2.5N

C

0.5N

D

1.0N

##### Explanation

Upthrust = change in weight

density = $$\frac{\text{mass}}{\text{volume}}$$

Mass of liquid displaced = Density of Liquid $$\times$$ Volume;

= 103 $$\times$$ 50 $$\times$$ 10-6m3

= 0.05kg

(Note that the volume of 50cm3 was converted to m3 by multiplying by 106) i.e 50cm3 = 50 $$\times$$ 10?6m3)

Since mass displaced = 0.05kg

Upthrust = mg = 0.05 $$\times$$ 10

= 0.5N

Question 6
A
High pressure and low voltage
B
High pressure and high voltage
C
Low pressure and low voltage
D
Low pressure and high volatge
##### Explanation
Cathode rays are produced in a discharge tube under Low pressure and high voltage

Question 7
A
A man supports a heavy food above his head with his hands
B
A boy climbs onto a table
C
A man pushes unto a table
D
A woman holds a pot of water
##### Explanation
For work to be done, distance must be involved because
workdone = force $$\times$$ distance

Question 8
A

7.53 x 105 Jkg$$^{-1}$$

B

7.53 x 10-2Jkg$$^{-1}$$

C

7.53 x 104Jkg$$^{-1}$$

D

7.53 x 10-3Jkg$$^{-1}$$

##### Explanation

Latent Energy = mass(m) $$\times$$ specific latent heat (L)
E = mL

L = $$\frac{E}{m}$$

= $$\frac{1.13 \times 10 ^{6}}{15}$$

= 7.53 $$\times$$ 104Jkg$$^{-1}$$

Question 9
A

12.00%

B

25.00%

C

33.30%

D

75.00%

##### Explanation

Internal resistance determine the maximum current that can be supplied

Efficiency =$$\frac{IR}{I(R + r)}$$ $$\times$$ 100

=$$\frac{I6}{I(6 + 2)}$$ $$\times$$ 100

= 75.00%

Question 10
A
Molecules of a liquid are stationary
B
Brownian motion is an evidence of particle nature of matter
C
Matter is made up of molecules
D
The molecules of matter are in constant motion
##### Explanation
Molecules of liquid are not stationary
Brownian motion is an evidence of particle nature of matter
matter is made up of molecules
The molecules of matter are in constant motion

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