The bond between silicon and germanium is
- A. dative
- B. covalent bond
- C. trivalent
- D. ionic
The energy of a photo having a wavelength of 10-10m is
(h= 6.63 x 10 -34Js, c =3.0 x 10 8ms-1)
- A. 2.0 x 10 -15J
- B. 1.7 x 10 -13J
- C. 2.0 x 10 -12J
- D. 1.7 x 10 -12J
The particle nature of light is demonstrated by the
- A. photoelectric effect
- B. speed of light
- C. colours of light
- D. diffraction of light
In photo-emission, the number of photo-electrons ejected per second depends on the?
- A. frequency of the beam
- B. work function of the metal
- C. threshold frequency of the metal
- D. intensity of the beam
Calculate the energy of the third level of an atom if the ground state energy is – 24.8eV
- A. -9.20eV
- B. -8.20eV
- C. -2.75eV
- D. -1.75eV
If a current of 2.5A flows through an electrolyte for 3 hours and 1.8g of a substance is deposited, what is the mass of the substance that will be deposited if a current of 4A flows through it for 4.8 hours?
- A. 2.4g
- B. 3.2g
- C. 4.6g
- D. 4.8g
Induced emfs are best explained using
- A. Ohm's law
- B. Faraday's law
- C. Colomb's law
- D. Lenz's law
To convert a galvanometer to a voltmeter, a
- A. high resistance is connected to it in series
- B. high resistance is connected to it in parallel
- C. low resistance is connected to it in parallel
- D. low resistance is connected to it in series
When a charge moves through an electric circuit in the direction of an electric force, it
- A. gains both potential and kinetic energy
- B. gains potential energy and lose kinetic energy
- C. loses potential energy and gains kinetic energy
- D. loses both potential and kinetic energy
An electric device is rated 2000W, 250V. Calculate the maximum current it can take
- A. 9A
- B. 8A
- C. 7A
- D. 6A
A house has ten 40W and five 100W bulbs. How much will it cost the owner of the house to keep them lit for 10 hours if the cost of a unit is 5N?
- A. N90
- B. N50
- C. N45
- D. N5
Which of the following obeys ohms laws?
- A. electroytes
- B. metals
- C. diode
- D. glass
A cell of emf 1.5V is connected in series with a 1Ω resistor and a current of 0.3A flows through the resistor. Find the internal resistance of the cell
- A. 4.0Ω
- B. 3.0Ω
- C. 1.5Ω
- D. 1.0Ω
Capacitors are used in the induction coil to
- A. control circuits
- B. prevent distortion of electric fields
- C. prevent electric sparks
- D. dissipate energy
Calculate the force acting on an electron of charge 1.5 x 10-19C placed in an electric field of intensity 105Vm-1
- A. 1.5x10-11N
- B. 1.5x10-12N
- C. 1.5x10-13N
- D. 1.5x10-14N
The angle of deviation of light of various colours passing through a triangular prism increases in the order
- A. red → green → blue
- B. green → violet → blue
- C. blue → red → green
- D. blue → green → red
If the linear magnification of the objective and eyepiece convex lenses of a compound microscope are 4 and 7 respectively. Calculate the angular magnification of the microscope
- A. 2
- B. 3
- C. 11
- D. 28
Total internal reflection will not occur when light travels from
- A. water to air
- B. water into glass
- C. glass to air
- D. glass into water
A ray of light passing through the centre of curvature of a concave mirror is reflected by the mirror at?
- A. 0o
- B. 45o
- C. 90o
- D. 180o
A man 1.5m tall is standing 3m in front of a pinhole camera whose distance between the hole and the screen is 0.1m. What is the height of the image of the man on the screen?
- A. 0.05m
- B. 0.15m
- C. 0.30m
- D. 1.00m
If a sonometer has a fundamental frequency of 450HZ, what is the frequency of the fifth overtone?
- A. 2700Hz
- B. 456Hz
- C. 444Hz
- D. 75Hz