In the diagram above, three identical lamps each of 100 W are connected in parallel across a potential difference of 250 V. Calculate the reading of the ammeter.
- A. 7.5A
- B. 2.5A
- C. 1.2A
- D. 0.8A
- E. O.4A
The function of the magnanese (IV) oxide in a leclanche cell is to
- A. decrease the e.m.f. of the cell
- B. prevent local action in the cell
- C. prevent polarization in the cell
- D. increase the density of the electrolyte
- E. increase the resistance of the cell.
A particle of charge 5C moves perpendicularly to a magnetic Held of magnitude C.01 T. If the velocity of the charge is 1.5ms’2, calculate the magnitude of the force exerted on the particle
- A. 0.050 N
- B. 0.075N
- C. 0.0300N
- D. 3.300N
- E. 0.000N
Which of the following have the greatest penetrating power?
- A. Beta rays
- B. Alpha rays
- C. Gamma rays
- D. Electrons
- E. Neutrons
The potential difference between two points A and B situated at a distance d apart is V. Which of the following expresses the magnitude of the electric field intensity between the two points assuming the field is uniform?
- A. Vd
- B. dV-1
- C. Vd-1
- D. V2d
- E. d2V
A point charge of 1.0 x 10-7 C experiences force of 0.01 N in a uniform electric field. Calculate the magnitude of the strength of the field
- A. 106 Vm-1
- B. 105 Vm-1
- C. 10-5 Vm-1
- D. 102 Vm-1
- E. 109 Vm-1
In a purely resistive a.c. circuit, the current I = Io sin wt and voltage, V = Vo sin wt. Calculate the instantaneous power dissipated in the circuit in time t.
- A. Io Vo
- B. 2Io Vosin wt
- C. (Io Vo)/2
- D. Io Vo sin2wt
- E. I2o V2o
The vector diagram shown below represents the resistance R, the capacitive reactance Xc, the inductive reactance Xc and the impedance, Z in an R-L-C circuit. The current in the circuit will be maximum when
- A. Xc = Xc
- B. XL = XL
- C. R = XL
- D. R =X
In a series R – C circuit, the resistance of the resistor is 4 Ξ© and capacitive reactance is 3 Ξ©. Calculate the impedance of the circuit
- A. 1Ξ©
- B. 4Ξ©
- C. 5Ξ©
- D. 7Ξ©
- E. 12Ξ©
What is the gravitational potential due to a point mass m at a distance from it? (G = gravitational constant)
- A. -Gm2/r2
- B. -Gm2/r
- C. βGm/Gr2
- D. βGm/r
- E. βGm/2
Calculate the escape velocity of a satellite launched from the earthβs surface (Take g as 10ms-2 and the radius of the earth as 6.4 x 106m)
- A. 8.00 x 106ms-1
- B. 1.13 x104ms-1
- C. 3.58x102ms-1
- D. 5.59 x10-2ms-1
- E. 3.95x10-2ms-1
A household refrigerator consumes electrical energy at the rate of 200 W. lf electricity costs 5 k per kWh, calculate the cost of operating the appliance for 30 days.
- A. N7.20
- B. N12.00
- C. N30.00
- D. N33.33
- E. N72.00
The unit of inductance is
- A. farad
- B. henry
- C. hertz
- D. weber
- E. tesla
Which of the following instruments can be used to compare the relative magnitude of similar charges on two given bodies?
- A. Electrophorus
- B. Ebonite rod
- C. Proof plane
- D. Gold-leaf electroscope
- E. Capacitor
Which of the following indicates the correct sequence of steps taken in charging a gold-leaf electroscope by induction? l. Removing the ebonite rod ll. Bringing a negatively charged ebonite rod close to the cap III. Earthing the cap IV. Disconnecting the earthing
- A. III, II, I and IV
- B. II, I, III and IV
- C. III, IV II and I
- D. II, III, IV and I
- E. III, IV, I and II.
A short chain is usually attached to the back of a petrol tanker and trailing behind it so that the
- A. petrol tanker is balanced on the road
- B. heat generated by friction in the engine can be conducted to the earth
- C. charges generated by friction in the tanker are conducted to the earth
- D. tanker can move slowly as the chain touches the road surface
- E. chain can produce sound in resonance with the noise from the tankerβs engine
Which of the following is a percussion instrument?
- A. Flute
- B. Organ
- C. Bell
- D. Piano
- E. Sonometer
The quality of a note produced by a vibrating string is determined by the
- A. pitch of the note
- B. tension of the string
- C. material of the string
- D. presence of overtones
- E. thickness of the string
Which of the following is correct about light and sound waves?
- A. Both of them are associated with energy transfer
- B. Both of them need material media for propagation
- C. they are both longitudinal waves
- D. their velocities in air are equal
- E. Both of them can be polarized
A man stands in front of a tall wall and produces a sound. If he receives the echo of the sound two seconds later, calculate his distance from the wall. (The speed of sound in air is 330ms-1)
- A. 600m
- B. 400m
- C. 330m
- D. 328m
- E. 165m
Which of the following have the longest wavelengths?
- A. Infra-red rays
- B. Gamma rays
- C. X-rays
- D. Ultra-violet rays
- E. Radio waves