A machine has an efficiency of 60%. If the machine is required to overcome a load of 30 N with a force of 20 N calculate its mechanical advantage?

• A. 0.7
• B. 0.9
• C. 1.5
• D. 2.5

(a)(i) Define each of the following terms as it relates to converging lenses (i) focal length; (ii) optical Centre.

(iii) Draw a ray diagram to illustrate how a converging lens is used to produce a virtual image of an object.

(b)(i) Name the primary colors of light. (ii) Match each primary color to its corresponding complementary color.

(c) A ray passes symmetrically through a glass prism of angle 60° and refractive index of 1.5. Calculate the angle of: (i) incidence; (ii) minimum deviation.

A metal rod of length 40cm at 20°C is heated to a temperature of 45°C. If the new length of the rod is 40.05cm. Calculate its linear expansitivity

• A. 1.2 x \(10^{-5}K^{-1}\)
• B. 2.5x \(10^{-5}K^{-1}\)
• C. 3.5x \(10^{-5}K^{-1}\)
• D. 5x \(10^{-5}K^{-1}\)

The instrument used to view stars is the

• A. Prism binoculars
• B. Telescope
• C. Film projector
• D. Microscope

A real object is placed at a distance ucm in front of a curved mirror of focal length fcm. If the image is upright and magnified, then the mirror is

• A. convex and u =2f
• B. concave and u = 2f
• C. convex and u = f
• D. concave and u = f

A man stands 4m in front of a plane mirror. If the mirror is moved 1m towards the man, the distance between him and his new image is

• A. 3m
• B. 5m
• C. 6m
• D. 10m

The ice point of an ungraduated mercury-in-glass thermometer is X, while its steam point is 90^o. This thermometer reads 60^o when the true temperature is 40^oC Calculate the value of X.

• A. 60^o
• B. 48^o
• C. 40^o
• D. 30^o

A note is the octave of another note if it has

• A. a frequency twice that of the first note
• B. frequency half that of the first note
• C. the same fundamental frequency as the first one
• D. a frequency frequency eight times that of the first note

An object placed at the bottom of a well full of clear water appears closer to the surface due to?

• A) diffraction
• B) reflection
• C) refraction
• D) polarization

The quantity of heat energy required to melt completely 1 kg of ice at - 30^oC is [latent heat of fusion = 3.5 x 10⁵Jkg ^-1, specific heat capacity of ice = 2.1x10³Jkg ^-1K^-1]

• A. 4.13x¹⁰6J
• B. 4.13x10⁵J
• C. 3.56x10⁴J
• D. 3.56x10²J