Tea pots are often silver-coated to prevent heat loss by
- A. conduction only
- B. convention only
- C. convection and conduction
- D. radiation only
The change in volume when 450kg of ice is completely melted is
[density of ice = 900 kgm-3, density of water = 1000 kgm-3]
- A. 0.50m3
- B. 0.45m3
- C. 0.05m3
- D. 4.50m3
The phase difference between waves P and q in the diagram above is
- A. 2π
- B. π
- C. π/4
- D. π/2
When left in a freezer, a bottle full of water cracks on freezing into ice because of the
- A. increase in the volume of water
- B. contraction of the bottle
- C. expansion of the bottle
- D. decrease in the volume of water
The refractive index of the medium M in the diagram above is
- A. 1/√3
- B. 2√3
- C. √3
- D. 2/√3
If u is the object distance and v the image distance, which of the following expressions gives the linear magnification produced by a convex lens of focal length f?
- A. u/f - f
- B. u/v + f
- C. v/f + 1
- D. v/f - 1
The pitch of a sound note depends on
- A. timbre
- B. frequency
- C. harmonics
- D. quality
A person can focus an object only when it lies within 200cm from him. Which spectacles should be used to increase his maximum distance of distinct vision infinity
- A. Convex lens
- B. Binoculars
- C. Concave lens
- D. Plane glasses
A ray of light makes an angle of 35o with a plane mirror. What is the angle of reflection?
- A. 35o
- B. 55o
- C. 70o
- D. 65o
What happens to the rays in a parallel beam of light?
- A. They diverge as they travel
- B. they intersect
- C. They converge as they travel
- D. They meet at infinity.
What types of mirror are capable of producing parallel beams of light such as those arising from the headlamps of a car?
- A. Parabolic mirrors
- B. Plane mirrors
- C. Cylindrical mirrors
- D. Spherical mirrors
In which of the following material media will sound travel fastest?
- A. oil
- B. metal
- C. gas
- D. water
The earth is four times the size of the moon and the acceleration due to gravity on the earth is 80 times that on the moon. The ratio of the mass of the moon to that of the earth is
- A. 1:80
- B. 1:320
- C. 1:1280
- D. 1:4
the diagram above shows forces 4N, 6N, 10N and 8N which act at a point O in the directions indicated. the net horizontal force is
- A. 13N
- B. 17N
- C. √3N
- D. 7√3N
As the pressure of a fluid increases, its viscosity
- A. decreases
- B. increases
- C. increases then decreases
- D. remains constant
A 100kg box is pushed along a road with force of 500N. If the box moves with a uniform velocity, the coefficient of friction between the box and the road is
- A. 0.4
- B. 1.0
- C. 0.8
- D. 0.5
In a hydraulic press , a force of 40N is applied on the effort piston of area 0.4m2. If the force exerted on the load piston is 400N, the area of the large piston is
- A. 4m2
- B. 8m2
- C. 2m2
- D. 1m2
I. Jet propelled aircraft
II. Rocket propulsion
III. The recoil of a gun
IV. A person walking
Which of the above is based on Newton’s third law of motion
- A. I and II only
- B. I, II, III, and IV only
- C. I and III only
- D. I, II and III only
A machine whose efficiency is 60% has a velocity ratio of 5. If a force of 500N is applied to lift a load P, what is the magnitude of P?
- A. 1500N
- B. 500N
- C. 4166N
- D. 750N
A body of mass 4kg is acted on by a constant force of 12N for 3 seconds. The kinetic energy gained by the body at the end of the time is
- A. 144J
- B. 162J
- C. 81J
- D. 72J
If the angle between two vector P and Q is Oo, the vectors are said to
- A. intersect at the angle 45o
- B. intersect at the angle 60o
- C. be parallel
- D. be perpendicular