A straight wire 15cm long, carrying a current of 6.0A is in a uniform field of 0.40T. What is the force on the wire when it is at right angle to the field
- A. 0.46N
- B. 0.35N
- C. 0.36N
- D. 0,24N
The pin-hole camera produces a less sharply defined image when the
- A. pin-hole is larger
- B. illumination is less
- C. screen is further from the pin-hole
- D. object is further from the pin-hole
A ray of light passes through the centre of curvature of a concave mirror and strikes the mirror. At what angle is the ray reflected?
- A. 180\(^o\)
- B. 90\(^o\)
- C. 0\(^o\)
- D. 60\(^o\)
The distance between an object and its real image in a convex lens is 40cm. If the magnification of the image is 3, calculate the focal length of the lens
- A. 6.5 cm
- B. 7.5 cm
- C. 8.5 cm
- D. 4.5 cm
When the temperature of a liquid is increased, its surface tension?
- A. increases
- B. decreases
- C. remain constant
- D. increases then decreases
Ripple in a power supply unit is caused by
- A. using an alternating current source
- B. forward voltage drop
- C. heavy load
- D. using a zener diode
Which of the following equations is the correct definition of the reactance of an indicator L?
- A. Reactance = (Amplitude of voltage) \(\div\) (Amplitude of current)
- B. Reactance = (Amplitude of voltage) x (Amplitude of current)
- C. Reactance = (Amplitude of current)\(^2\) \(\div\) (Amplitude of voltage)
- D. Reactance = (Amplitude of current)\(^2\) \(\div\) (Amplitude of voltage)\(\frac{1}{2}\)
Which of the following is/are the limitations to the Rutherford’s atomic models?
I. It is applicable when energy is radiated as electrons are revolving
II. It is applicable when energy is radiated in a continuous mode
III. It is applicable to an atom with only one electron in the other shell
- A. I only
- B. II only
- C. I & II only
- D. I, II & III only
Electrons were discovered by
- A. Dalton
- B. James Charwick
- C. J.J. Thompson
- D. Niels Bohr
In a slide wire bridge, the balance is obtained at a point 25cm from one end of wire 1m long. The resistance to be tested is connected to that end and a standard resistance of 3.6\(\Omega\) is connected to the other end of the wire. Determine the value of the unknown resistance
- A. 3.2\(\Omega\)
- B. 1.4\(\Omega\)
- C. 3.21\(\Omega\)
- D. 1.2\(\Omega\)
During the transformation of matter from the solid to the liquid state, the heat supplied does not produce temperature increase because
- A. all the heat is used to break the bonds holding the molecules of the solid together
- B. the heat capacity has become very large as the substance melts
- C. the heat energy is quickly conducted away
- D. the heat gained is equal to the heat lost by the substance
Lamps in domestic lightings are usually in
- A. series
- B. divergent
- C. convergent
- D. parallel
A train has an initial velocity of 44m/s and an acceleration of -4m/s\(^2\). Calculate its velocity after 10 seconds
- A. 10m/s
- B. 6m/s
- C. 8m/s
- D. 4m/s
According to kinetic molecular model, in gases
- A. The molecule are very fast apart & occupy all the space made available
- B. The particles occur in clusters with molecules slightly farther apart
- C. The particles vibrate about fixed positions and are held together by the strong intermolecular bond between them
- D. The particles are closely packed together, they occupy minimum space & are usually arranged in a regular pattern
A metal rod has a length of 100cm at 200\(^oC\). At what temperature will its length be 99.4cm. If the linear expansivity of the material of the rod is 2 x 10\(^{-5}C^{-1}\)
- A. 200\(^o\)C
- B. 300\(^o\)C
- C. 100\(^o\)C
- D. -100\(^o\)C
When blue and green colours of light are mixed, the resultant colour is
- A. cyan
- B. magenta
- C. black
- D. yellow
If a body moves with a constant speed and at the same time undergoes an acceleration, its motion is said to be
- A. oscillation
- B. circular
- C. rotational
- D. rectilinear
The limiting frictional force between two surface depends on
I. the gaseous reaction between the surfaces
II. the nature of the surfaces in contact
III. the relative velocity between the surfaces
- A. I only
- B. I & IV only
- C. II only
- D. III only