The diagram above represents the stress-strain graph for a typical metal rod. What does the X represent?
- A. Breaking point
- B. Yield point
- C. Elastic limit
- D. Proportional limit
If the distance between two point charges its increased by a factor of four, the magnitude of the electrostatic force between them will be
- A. 1/4 of its former value
- B. 1/16 of its former value
- C. 1/2 of its former value
- D. 4 times its former value
The figure above shows three capacitors, 2μF, 3μF and 6μF connected in series. If the p.d across the system is 12V, the p.d, across the 6μF capacitor is
- A. 4V
- B. 12V
- C. 2V
- D. 6V
106J of heat is required to boil off completely 2kg of a certain liquid. Neglecting heat lost to the surroundings, the latent heat of vaporization of the liquid is
- A. 2.0 x 106J kg-1
- B. 5.0 x 106J kg-1
- C. 2.0 x 105J kg-1
- D. 5.0 x 105J kg-1
Two liquids L1 and L2 are contained in a U – tube. The height and the density of L1 are 8 cm and 103 kgm-3 respectively. If the density of L2 is 800 kgm-3, its height measured from the same level is
- A. 8 cm
- B. 10 cm
- C. 16 cm
- D. 12 cm
\( ^{235} _{92}U + ^1 _0n → ^{144} _{56}Ba + ^{90} _{36}Kr +2X \)
In the reaction above, X is
- A. electron
- B. proton
- C. neutrino
- D. neutron
In the circuit diagram of a transistor above, the terminal P, Q and R represent
- A. EMITTER, BASE and COLLECTOR
- B. COLLECTOR, EMITTER and BASE
- C. BASE, COLLECTOR and EMITTER
- D. BASE, ENITTER and COLLECTOR
In the figure above, the work done by the force of 100N inclined at an angle of 60o to the object dragged horizontally to a distance of 8m is
- A. 800J
- B. 600J
- C. 100J
- D. 400J
If the system above is in equilibrium, the tension in the string Q is
- A. 11N
- B. 9N
- C. 4N
- D. 6N
In the figure above, the coefficient of static friction is 0.5. If the tension in the string is T, the acceleration of the system in motion is
- A. 5 ms-2
- B. 15 ms-2
- C. 3 ms-2
- D. 9 ms-2
The value of F in the figure above when in equilibrium is
- A. 10N
- B. 12N
- C. 20N
- D. 27N
The figure above shows a plot of angles of deviation through a glass prism when light is incident at θ degrees on the prism. The incident angle that produces the minimum deviation is
- A. 20o
- B. 18o
- C. 35o
- D. 25o
When a pentavalent impurity is added to a pure semiconductor, it becomes?
- A. a p-type semiconductor
- B. an n-type semiconductor
- C. an insulator
- D. an intrinsic semi-conductor
Which of the following can conduct electricity owing to the presence of free mobile electrons?
- A. germanium
- B. silicon
- C. grapefruit
- D. copper
Thermionic emission is the process whereby?
- A. β - rays are produced
- B. holes are produced
- C. x - rays are produced
- D. electrons leave a hot element
A piece of radioactive material contains 10\(^{20}\) atoms.
If the half life of the material is 20 seconds, the number of disintegration in the first second is?
- A. 3.47 x 1018
- B. 6.93 x 10 20
- C. 3.47 x 1020
- D. 6.93 x 1018
If the decay constant of a radioactive substance is 0.231s-\(^1\), the half-life is?
- A. 3.00 s
- B. 0.12 s
- C. 0.33 s
- D. 1.50 s
Cancerous cells can be destroyed by?
- A. ultraviolet rays
- B. alpha particules
- C. x - rays
- D. infrared rays
A band of 500 rectangular loops of wire of area 20 cm by 20 cm, encloses a region of magnetic field which charges from 1.0T to 0.4T within 5 seconds, calculate the induced e.m.f.
- A. 5.60 v
- B. 24.00 v
- C. 0.24 v
- D. 2.40 v
An electric lamp marked 240v, 60 W is left to operate for an hour. How much energy is generated by the filament?
- A. 3.86 x 105J
- B. 3.56 x 105J
- C. 1.80 x 104J
- D. 2.16 x 105J
If negative charges are induced on an electroscope and a positively charged rod is brought near the cap of the electroscope, the leaves will?
- A. close up
- B. become positively charged
- C. become negatively charged
- D. open further