2023 Physics

1.

• A. Diffraction
• B. Refraction
• C. Polarisation
• D. Interference

2. Which of the following statements regarding the application of electrical conduction via gases is/are correct?
Electrical conduction in gas is applied in:
(i) The identification of gases
(ii) Lighting/fluorescent tubes
(iii) Photocells
(iv) Cathode ray oscilloscope/T.V. tubes

• A. (i), (iii) and (iv) only
• B. (i), (ii) and (iv) only
• C. (ii), (iii) and (iv) only
• D. (i), (ii) and (iii) only

3.

Find the tension in the two cords shown in the figure above. Neglect the mass of the cords, and assume that the angle is 38° and the mass m is 220 kg

[Take g = 9.8 ms-2]

• A. T₁ = 2864 N, T₂= 3612 N
• B. T₁= 3612 N, T₂ = 2864 N
• C. T₁= 3502 N, T₂= 2760 N
• D. T₁ = 2760 N, T₂ = 3502 N

4. A missile is launched with a speed of 75 ms-1 at an angle of 22° above the surface of a warship. Find the horizontal range achieved by the missile. Ignore the effects of air resistance.

[Take g = 10 ms-2]

• A. 195
• B. 271 m
• C. 391 m
• D. 136 m

5.

On a particular hot day, the temperature is 40°C and the partial pressure of water vapor in the air is 38.8 mmHg. What is the relative humidity?

• A. 70
• B. 62
• C. 80
• D. 42

6. Calculate the absolute pressure at the bottom of a lake at a depth of 32.8 m. Assume the density of the water is 1 x 10^3 kgm^-3 and the air above is at a pressure of 101.3 kPa.

[Take g = 9.8 ms^-2]

• A. 422.7
• B. 220.14
• C. 464.53
• D. 321.74

7. The terminals of a battery of emf 24.0 V and internal resistance of 1.0 Ω is connected to an external resistor 5.0 Ω. Find the terminal p.d.

• A. 18.0V
• B. 12.0V
• C. 16.0V
• D. 20.0V

8. A lorry accelerates uniformly in a straight line with acceleration of  4ms⁻²and covers a distance of 250 m in a time interval of 10 s. How far will it travel in the next 10 s?

• A. 650
• B. 900
• C. 800
• D. 250

9. The half life of a radioactive material is 12 days. Calculate the decay constant.

• A. 0.8663 day⁻¹
• B. 0.04331 day⁻¹
• C. 0.17325 day⁻¹
• D. 0.05775 day⁻¹

10. The number of holes in an intrinsic semiconductor

• A. is not equal to the number of free electrons
• B. is greater than the number of free electrons
• C. is equal to the number of free electrons
• D. is less than the number of free electrons

11.

Name the type of equilibrium for each position of the ball

• A. A – unstable, B – neutral, C – stable
• B. A – stable, B – neutral, C – unstable
• C. A – stable, B – unstable, C – neutral
• D. A – unstable, B – stable, C – neutral

12. Rainbow formation is as a result of the combination of which of the following phenomena?
    (i) Reflection
    (ii) Dispersion
    (iii) Total internal reflection
    (iv) Refraction

• A. (ii) and (iv) only
• B. (i), (iii) and (iv) only
• C. (ii), (iii) and (iv) only
• D. (i), (ii) and (iv) only

13. The surface temperature of a swimming pool on a warm day is 25⁰C and the temperature at the bottom is 15⁰C. If the swimming pool has a surface area of 620 m²and a depth of 1.5m. Find the rate at which energy is transferred by conduction from the surface to the bottom of the swimming pool.

    [Thermal conductivity of water (k) = 0.6071 Wm^-1K^-1]

• A. 2.5kw
• B. 250kw
• C. 300kw
• D. 3.0kw

14. Which process is responsible for production of energy in stars?

• A. Nuclear reaction
• B. Nuclear fission
• C. Nuclear fusion
• D. Radioactive decay

15. How much net work is required to accelerate a 1200 kg car from 10ms⁻¹to 15ms⁻¹

• A. 1.95×10⁵j
• B. 1.35×10⁴j
• C. 7.5×10⁴j
• D. 6.0×10⁴j

16. A wire of radius 0.2 mm is extended by 0.5% of its length when supported by a load of 1.5 kg. Determine the Young’s modulus for the material of the wire.

[Take g = 10 ms−2−2]

• A. 2.4×10¹⁰(Nm⁻²)
• B. 1.5×10¹⁰(Nm⁻²)
• C. 2.4×10⁹(Nm⁻²)
• D. 1.3×10¹⁰(Nm⁻²)

17. A man swung an object of mass 2 kg in a circular path with a rope 1.2 m long. If the object was swung at 120 rev/min, find the tension in the rope.

• A. 400
• B. 288
• C. 240
• D. 379

18.

A 200 kg load is raised using a 110 m long lever as shown in the diagram above. The load is 10m from the pivot P. If the efficiency of the the lever is 80%, find the effort E required to lift the load.

[Take g = 10ms-2]

• A. 250
• B. 300
• C. 450
• D. 200

19. An air bubble of radius 4.5 cm initially at a depth of 12 m below the water surface rises to the surface. If the atmospheric pressure is equal to 10.34 m of water, the radius of the bubble just before it reaches the water surface is

• A. 6.43 cm
• B. 8.24 cm
• C. 4.26 cm
• D. 5.82 cm

20. A parallel plate capacitor separated by an air gap is made of 0.8m²tin plates and 20 mm apart. It is connected to 120 V battery. What is the charge on each plate?

    Take ε_o= 8.85×10⁻¹²Fm⁻¹

• A. 3.54nC
• B. 42.5nC
• C. 35.4nC
• D. 4.25nC

21. What is the amount of heat required to raise the temperature of a 0.02 kg of ice cube from −10^oC to 10^oC ?
    
    [specific latent heat of fusion of ice = 3.34 x 105105  Jkg−1Jkg−1, Specific heat capacity of water = 4200 Jkg⁻¹J ^k−1

Specific heat capacity of ice = 2100 Jkg−1Jkg⁻¹ k⁻¹

• A. 6680 J
• B. 1680 J
• C. 7520 J
• D. 7940 J

22. Which of the following thermometers measures temperature from the thermal radiation emitted by objects?

• A. Pyrometer thermometer
• B. Platinum resistance thermometer
• C. Thermocouple thermometer
• D. Constant pressure gas thermometer

23.

A 400 N box is being pushed across a level floor at a constant speed by a force P of 100 N at an angle of 30.0° to the horizontal, as shown in the the diagram below. What is the coefficient of kinetic friction between the box and the floor?
 

• A. 0.19
• B. 0.24
• C. 0.40
• D. 0.22

24. Light of wavelength 589 nm in vacuum passes through a piece of fused quartz of index of refraction n = 1.458. What is the frequency of the light in fused quartz?
    
    [Speed of light c = 3.00×108ms−13.00×108ms−1]

• A. 5.09×10¹⁵Hz
• B. 5.09×10¹⁴Hz
• C. 1.77×10¹⁵Hz
• D. 1.77×10¹⁴ Hz

25. A simple pendulum, has a period of 5.77 seconds. When the pendulum is shortened by 3 m, the period is 4.60 seconds. Calculate the new length of the pendulum

• A. 5.23 m
• B. 6.42 m
• C. 4.87 m
• D. 7.26 m

26.

Three forces with magnitudes 16 N, 12 N and 21 N are shown in the diagram below. Determine the magnitude of their resultant force and angle with the x-axis

• A. 7.63N,61°
• B. 8.71N,61°
• C. 7.63N,29°
• D. 8.71N,29°

27. A travelling wave of amplitude 0.80 m has a frequency of 16 Hz and a wave speed of 20 ms⁻¹

Calculate the wave number of the wave.

• A. 3
• B. 4
• C. 5
• D. 2

28. The near point of a patient’s eye is 50.0 cm. What power (in diopters) must a corrective lens have to enable the eye to see clearly an object 25.0 cm away?

• A. 2 diopters
• B. 2.5 diopters
• C. 0.5 diopters
• D. 3 diopters

29. Which of the following is/are nottrue about the heat capacity of a substance?
    (i) It is an intensive property
    (ii) Its S.I unit is jK⁻¹j
    (iii) It is an extensive property
    (iv) Its S.I unit is jkg⁻¹

• A. (i) and (iii) only
• B. (i), (ii) and (iv) only
• C. (i) and (iv) only
• D. (ii) and (iii) only

30. The pinhole camera works on

• A. the principle of the reversibility of light
• B. the principle of the rectilinear propagation of light
• C. Huygen’s principle
• D. the principle of total internal reflection of light

31. A step-down transformer is used on a 2.2 kV line to deliver 110 V. How many turns are on the primary windings if the secondary has 25 turns?

• A. 20
• B. 250
• C. 200
• D. 500

32.

A block of mass 0.5 kg is suspended at the 40 cm mark of a light metre rule AB that is pivoted at point E, the 90 cm mark, and is kept at equilibrium by a string attached at point D, the 60 cm mark, as shown in the figure above. Find the tension T in the string.

[Take g = 10ms⁻²10ms⁻² ]

• A. 16.67N
• B. 15.67N
• C. 14.67N
• D. 18.67N

33. A 35 kΩ is connected in series with a resistance of 40 kΩ. What resistance R must be connected in parallel with the combination so that the equivalent resistance is equal to 25 kΩ?

• A. 40 kΩ
• B. 37.5 kΩ
• C. 45.5 kΩ
• D. 30 kΩ

34. A piano wire 50 cm long has a total mass of 10 g and its stretched with a tension of 800 N. Find the frequency of the wire when it sounds its third overtone note.

• A. 800 Hz
• B. 600 Hz
• C. 400 Hz
• D. 200 Hz

35. An object is placed 35 cm away from a convex mirror with a focal length of magnitude 15 cm. What is the location of the image?

• A. 26.25 cm behind the mirror
• B. 10.5 cm behind the mirror
• C. 26.25 cm in front of the mirror
• D. 10.5 cm in front of the mirror

36. A relative density bottle has a mass of 19 g when empty. When it is completely filled with water, its mass is 66 g. What will be its mass if completely filled with alcohol of relative density 0.8?

• A. 47 g
• B. 52.8 g
• C. 37.6 g
• D. 56.6 g

37. How much work is done against the gravitational force on a 3.0 kg object when it is carried from the ground floor to the roof of a building, a vertical climb of 240 m?

• A. 7.2 kJ
• B. 4.6 kJ
• C. 6.8 kJ
• D. 8.4 kJ

38. A beam of light travelling in water is incident on a glass which is immersed in the water. The incident beam makes an angle of 40o40o with the normal. Calculate the angle of refraction in the glass.
    
    [Refractive index of water = 1.33, Refractive index of glass = 1.5]

• A. 29.36^o
• B. 25.37^o
• C. 37.21^o
• D. 34.75^o

39. An open-tube mercury manometer is used to measure the pressure in a gas tank. When the atmospheric pressure is 101,325 Pa, what is the absolute pressure in Pa in the tank if the height of the mercury in the open tube is 25 cm higher. density of mercury = 13600kg/m³ ,g=9.8m/s213600kg/m³ ,g=9.8m/s²

• A. 108,986 Pa
• B. 165,238 Pa
• C. 122,364 Pa
• D. 134,645 Pa

40. The sensitivity of a thermometer is

• A. All of the above
• B. how quickly a temperature change can be detected
• C. the difference between the maximum and the minimum temperature
• D. the smallest temperature change that can be detected or measured

41.

The diagram above illustrates the penetrating power of some types of radiation. X, Y and Z are likely

• A. X = α-particle; Y = γ-ray; Z = β-particle
• B. X = α-particle; Y = β-particle; Z = γ-ray
• C. X = γ-ray; Y = α-particle; Z = β-particle
• D. X = β-particle; Y = γ-ray; Z = α-particle

42. An explosion occurs at an altitude of 312 m above the ground. If the air temperature is -10.00°C, how long does it take the sound to reach the ground?
    
    [velocity of sound at 0oC0oC = 331 ms^-1]

• A. 0.94s
• B. 0.96s
• C. 0.93s
• D. 0.95s

43. A charge of 4.6×10⁻⁵C is placed in an electric field of intensity 3.2×10⁴Vm⁻¹. What is the force acting on the electron?

• A. 1.5 N
• B. 3.7 N
• C. 4.2 N
• D. 2.5 N

44. The branch of physics that deals with the motion of objects and the forces acting on them is called:

• A. Electromagnetism
• B. Thermodynamics
• C. Mechanics
• D. Quantum mechanics

45. The working of the beam balance is based on the principle of

• A. moments
• B. conservation of energy
• C. equivalence
• D. floatation

46. Which of the following is a type of incandescent light source?

• A. Fluorescent lamp
• B. LED lamp
• C. Tungsten filament lamp
• D. Neon lamp

47.

From the diagram above, if the potential difference across the resistor, capacitor and inductor are 60V, 120V and 30V respectively, the effective potential difference is

• A. 81
• B. 67
• C. 59
• D. 73

48. When light of a certain frequency is incident on a metal surface, no photoelectrons are emitted. If the frequency of the light is increased, what happens to the stopping potential?

• A. The stopping potential does not change.
• B. The stopping potential decreases.
• C. The stopping potential can either increase or decrease, depending on the intensity of the light.
• D. The stopping potential increases.

49. Which of the following is NOT a limitation of experimental measurements?

• A. Systematic error
• B. Instrument resolution
• C. Random errors
• D. Human error

50. Which of the following liquids has the highest surface tension?

• A. Soapy water
• B. Water
• C. Mercury
• D. Oil