The note produced by a stretched string has a fundamental frequency of 400Hz. If the length of the string is doubled while the tension in the string is increased by a factor of 4, the frequency is
- A. 200Hz
- B. 400Hz
- C. 800Hz
- D. 1600Hz
A pipe of length 45cm is closed at the end. Calculate the fundamental frequency of the sound wave generated in the pipe if the velocity of sound in air is 360ms-1 [Neglect end correction]
- A. 5.5Hz
- B. 148.5Hz
- C. 200.0Hz
- D. 550.0Hz
The fundamental frequency of vibration of a sonometer wire may be halved by
- A. doubling the length of the wire
- B. doubling the mass of the wire
- C. reducing the tension by half
- D. reducing the absolute temperature by half
The sound from a source travelled to the bottom of the sea and the echo was heard 4s later. If the speed of sound in sea water is 1500ms-1 the depth of the sea is
- A. 6000m
- B. 3000m
- C. 1500m
- D. 375m
The equation of transverse wave traveling along a string is given by Y = 0.3 sin(0.5x – 50t) where Y and X are in cm and t is in seconds.Find the maximum displacement of the particles from the equilibrium position
- A. 50.0cm
- B. 2.5 cm
- C. 0.5cm
- D. 0.3cm
Two similar kettles containing equal masses of boiling water are placed on a table. If the surface of one is highly polished and the surface of the other is covered with soot, Which of the following observations is correct
- A. The two kettles will cool down at the same rate
- B. the polished kettle cools down more quickly by conduction
- C. the kettle covered with soot cools down more quickly because it is a good radiator
- D. the kettle covered with soot cools down more quickly by the process of heat convection
If a room is saturated with water vapour, the temperature of the room must be
- A. at 0oC
- B. above the dew point
- C. at 100oC
- D. below or at the dew point
Heat is supplied to a test tube containing 100g of ice at its melting point. The ice melts completely in 1 min.What is the power rating of the source of heat? [Latent heat of fusion of ice = 336Jg-1]
- A. 336W
- B. 450W
- C. 560W
- D. 600W
When 100g of liquids L1 at 78°C was mixed with Xg of liquid L2 at 50°C, the final temperature was 66°C. Given that the specific heat capacity of L2is half that of L1, find x
- A. 50g
- B. 100g
- C. 150g
- D. 200g
A Motor Tyre is inflated to pressure of 2.0 x 105Nm-2 when the temperature of air is 27oC. What will be the pressure in it at 87oC assuming that the volume of the Tyre does not change?
- A. 2.6 x 105Nm-2
- B. 2.4 x 105Nm-2
- C. 2.2 x 105Nm-2
- D. 1.3 x 105Nm-2
The melting point of naphthalene is 78oC. What is this temperature in kelvin
- A. 100k
- B. 351k
- C. 378k
- D. 444k
If a solid X floats in liquids P of relative density 2.0 and in liquid Q of relative density 1.5, it can be inferred that the
- A. weight of P displaced is greater than that of Q
- B. weight of P displaced is less than that of Q
- C. volume of P displaced is greater than that of Q
- D. volume of P displaced is less than that of Q
The mass of a specific gravity bottle is 15.2g when it is empty. it is 24.8g when filled with kerosene and 27.2g when filled with distilled water. Calculate the relative density of kerosene
- A. 1.25
- B. 1.10
- C. 0.90
- D. 0.80
Which of these statements are TRUE of pressure in liquids? i. pressure acts equally in all direction. ii. pressure decreases with depth. iii. pressure at the same level of a liquid is the same. iv pressure is dependent on the cross-sectional area of the barometer tube
- A. i, iii only
- B. i, ii, iii only
- C. i, iii, and iv only
- D. i, ii, iii and iv
A force of 15N stretches a spring to a total length of 30cm. An additional force of 10N stretches the spring 5cm further. Find the natural length of the spring
- A. 25.0cm
- B. 22.5cm
- C. 20.0cm
- D. 15.0cm
Calculate the velocity ratio of a screw jack of pitch 0.3cm if the length of the tommy bar is 21cm
- A. \(\frac{1}{140}\)\(\pi\)
- B. 14\(\pi\)
- C. 70\(\pi\)
- D. 140\(\pi\)
Calculate the magnitude of the force required to just move a 20kg object along a horizontal surface if the coefficient of friction is 0.2. [g = 10ms-2]
- A. 400.0N
- B. 40.0N
- C. 4.0N
- D. 0.4N
A cone in an unstable equilibrium has its potential energy
- A. decreased
- B. increased
- C. unchanged
- D. oscillating
An object of mass 50kg is released from a height of 2m.Find the kinetic energy just before it strikes the ground
- A. 250J
- B. 1000J
- C. 10 000J
- D. 100 000J
Which of the following is TRUE of a particle moving in a horizontal circle with constant angular velocity?
- A. The energy is costant but the linear momentum varies
- B. The linear momentum is conatant but the energy varies
- C. both energy and linear momentum are constant
- D. The speed and the linear velocity are both constant
A motor vehicle is brought to rest from a speed of 15ms-1 in 20 seconds. Calculate the retardation.
- A. 0.75ms-1
- B. 1.33ms-2
- C. 5.00ms-2
- D. 7.50ms-2