In a resonance tube experiment, the effective length of the air column for the first resonance is 20cm when set into vibration by a tuning fork of frequency 480Hz. Neglecting and effect, the velocity of sound in air is
- A. 96ms-1
- B. 255ms-1
- C. 340ms-1
- D. 384ms-1
When light is incident on an object which is magenta in colour, which of the following colour would be absorbed?
- A. Red and blue
- B. Green only
- C. Red and green
- D. Red only
For a short sighted person, light rays from a point on a very distant object is focused
- A. in front of the retina
- B. on the retina by a converging lens
- C. behind the retina by a diverging lens
- D. in front of the retina, a distance 2F from the lens
What must be the distance between an object and a converging lens of focal length 20cm to produce an erect image two times the object height?
- A. 20cm
- B. 15cm
- C. 10cm
- D. 5cm
A boy looks at the image of an object in a plane mirror. He observes two images, a main bright one and the other faint. The observed images result from?
- A. reflection only
- B. refraction only
- C. diffraction and interference
- D. reflection and refraction
- E. reflection and diffraction
An object which is 3cm high is placed vertically 10cm in front of a concave mirror. If this object produces an image 40cm from the mirror, the height of the image is
- A. 0.75cm
- B. 4.00cm
- C. 8.00cm
- D. 12.00cm
Shadows and eclipses result from the
- A. refraction of light
- B. rectilinear propagation of light
- C. defraction of light
- D. reflection of light
A wave disturbance travelling in air enters a medium in which its velocity is less than that in air. Which of the following statements is true about the wave medium?
- A. both the frequency of the wave and the wavelength are decreased
- B. the frequency of the wave is decreased while the wavelength is increased
- C. the frequency of the wave is unaltered while the wavelength is decreased
- D. the frequency of the wave is decreased while the wavelength is unaltered
A light wave of frequency 5 x 10\(^{14}\)Hz moves through water which has a refractive index of \(\frac{4}{3}\). Calculate the wavelength in water if the velocity of light in air is 3 x 10\(^8\)ms\(^{-1}\)
- A. 4.5 x 10-7m
- B. 6.0 x 10-7m
- C. 1.7 x 106m
- D. 2.2 x 106m
Which of the following statements are correct? i. land and sea breezes are natural convection currents. ii. convection may occur in liquids or gasses but not in solids. iii. the vacuum in a thermos flask prevents heat loss due to convection only.
- A. i and ii only
- B. i and iii only
- C. i and iii only
- D. i, ii, and iii
Which of the following conditions will make water boil at a temperature of 100oC when the atmospheric pressure is 750mmHg?
- A. increase the external pressure
- B. reduce the external pressure
- C. heat more rapidly at the same pressure
- D. reduce the external pressure by a quarter
1kg of copper is transferred quickly from boiling water to a block of ice. Calculate the mass of ice melted, neglecting heat loss. [specific heat capacity of copper 400Jkg-1K-1 and latent heat of fusion of ice 333 x 103Jkg-1]
- A. 60g
- B. 67g
- C. 120g
- D. 133g
The pressure of a gas when cooled at constant volume will decrease because the molecules
- A. collide less frequently with the walls of the container
- B. have the same average kinetic energy
- C. break up into smaller molecules
- D. decrease in number
A bar of initial length /0 is heated through a temperature change \(\Delta\)t to a new length I. The linear expansivity, a, of the bar is
- A. \(\frac{/ - /_o}{/ \Delta t}\)
- B. \(\frac{/ - /_o}{/_o \Delta t}\)
- C. /o(1 + \(\Delta\) t)
- D. \(\frac{/ - /_o}{/(1 + \Delta t)}\)
The resistances of platinum wire at the ice and steam points are 0.75 ohm and 1.05 ohm respectively. Determine the temperature at which the resistance of the wire is 0.90 ohm
- A. 43.0oC
- B. 50.0oC
- C. 69.9oC
- D. 87.0oC
40m3 of liquid is mixed with 60m3 of another liquid Q. If the density of P and Q are 1.00kgm-3 and 1.6kgm-3 respectively, what is the density of the mixture?
- A. 0.05kgm-3
- B. 1.25kgm-3
- C. 1.30kgm-3
- D. 1.36kgm-3
What is the length of liquid column in a barometer tube that would support an atmospheric pressure of 102000Nm-2 if the density of the liquid is 2600kgm-3? [g = 10ms-2]
- A. 0.75m
- B. 0.76m
- C. 3.92m
- D. 39.23m
An inclined plane which makes an angle of 30o with the horizontal has a velocity ratio of
- A. 2
- B. 1
- C. 0.866
- D. 0.50
A body of mass 10kg rests on a rough inclined plane whose angle of tilt \(\theta\) is variable. \(\theta\) is gradually increased until the body starts to slide down the plane at 30o. The coefficient of limiting friction between the body and the plane
- A. 0.30
- B. 0.50
- C. 0.58
- D. 0.87
A stone of mass m kg is held h meters above the floor for 50s. The work done in joules over this period is
- A. mh
- B. mgh
- C. \(\frac{mgh}{50}\)
- D. O
To keep a vehicle moving at a constant speed v, requires power P, from the engine. The force provided by the engine is
- A. \(\frac{p}{v}\)
- B. \(\frac{1}{2}\) v
- C. pv
- D. \(\frac{p}{v^2}\) v