I. The number of neutrons released exceeds the number that caused the fission.
II. There is loss of mass.
III. Energy is produced.
IV. Smaller nuclei merge to form larger nuclei
which of the statement above are correct about nuclear fission?
- A. II,III and IV only
- B. I, II and IV only
- C. I,II and III only
- D. I, III and IV only
The theory of electronic conduction in solids, which satisfactorily explains the properties of conductors, insulators and semi-conductor,is?
- A. string theory
- B. particle theory
- C. group theory
- D. band theory
A radioactive element has a half life of 4 days. The fraction that has decayed in 16 days is?
- A. (15)/16
- B. (1)/16
- C. (3)/4
- D. (1)/4
One of the properties of gamma rays is that they are?
- A. neutral
- B. massive
- C. positively charged
- D. negatively charged
The battery connection that permits current to flow across a p-n junction is called?
- A. reverse baised
- B. forward baised
- C. amplification.
- D. rectification
The process through which free electrons leave the surface of hot metal is known as?
- A. photon emission
- B. photo emission
- C. thermionic emission
- D. electron emission
The energy associated with the emitted photon when a mercury atom changes from one state to another is 3.3 ev. calculate the frequency of the photon.
[e = 1.6 x 10-19c; h = 6.6 x 10-13js]
- A. 1.3 x 10-15 Hz
- B. 3.1 x 1052 Hz
- C. 3.2 x 10-53 Hz
- D. 8.0 x 1014 Hz
I. Work done by load is always less than the work done by effort.
II. All machines are made of levers, pulleys, screws and gear wheels.
III. A fishing rod is a machine.
Iv. Effort is always larger than load.
which of statements above about machines are true?
- A. II and III
- B. III and IV
- C. I and III
- D. II and iv
The correct unit of energy density is?
- A. kg m3 s-2
- B. kg m2 s-2
- C. kg m-3 s-2
- D. kg m-1 s-2
The component of vector X along the direction of vector Y is zero when
- A. X and Y are in opposite directions to each other
- B. X is at an angle of 45° to Y
- C. X is perpendicular to Y
- D. X and Y are parallel to each other
If the radius of the earth is 6.4 x 10\(^6\)m, the escape velocity of a satellite from the earth is?
[g = 10 ms-2]
- A. 1.13 x 104 ms-1
- B. 9.00 x 103 ms-1
- C. 8.00 x 103 ms-1
- D. 1.27 x 104 ms-1
In an experiment to determine terminal velocity, as the pressure increases, the viscosity off a liquid
- A. increases
- B. decreases
- C. increases then decreases
- D. remains constant
The motion of smoke particles from a chimney is typical of?
- A. random motion
- B. circular motion
- C. rotational motion
- D. oscillatory motion
An ammeter of resistance 5⌠has a full-scale deflection when a current of 50 mA flows in it. The value of the resistor required to adapt it to measure a current of 5 A is?
- A. 0.25âŚ
- B. 5.00âŚ
- C. 19.80âŚ
- D. 0.05âŚ
When a certain a.c supply is connected to a lamp, it lights with the same brightness as it does with a 12 V d.c battery. Then r.m.s value of the a.c supply is?
- A. 12.0 V
- B. 3.5 V
- C. 17.0 V
- D. 8.5
During electrolysis, 2.0 g of a metal is deposited using a current of 0.5 A in 3 hours. The mass of the same metal which can be deposited using a current of 1.5 A in 1 hour is?
- A. 1.0 g
- B. 0.5 g
- C. 3.0 g
- D. 2.0 g
The electrolyte in the Nickei-iron (Nife) accumulator is
- A. potassium hydroxide solution
- B. dilute tetraoxosulphate(VI)acid
- C. copper tetraoxosulphate(VI)solution
- D. ammonium chloride solution
When an a.c. voltage is applied to a capacitor, no power is consumed because the current
- A. leads the voltage by 90°
- B. lags behind the voltage by 90°
- C. and voltage are in phase
- D. and voltage are 180° out of phase
If the capacitance of an capacitor is C = (ÎľA)/d, which of the following parameters is varied when a variable capacitors is used for tuning radio sets?
- A. constant (Îľ) and area
- B. area and distance.
- C. constant (Îľ) only
- D. distance only
An electric heater with a p.d of 240 V connected across its terminals has a total resistance of 960âŚ. find the power rating of the heater.
- A. 0.25 W
- B. 4.00 W
- C. 38.40W
- D. 60.00W
The main purpose of the transformer in an a.c radio set is to?
- A. increase power to the radio
- B. step up the voltage
- C. convert energy from a.c to d.c
- D. step down the voltage