Uranium of atom number 92 and mass number 238 emits an alpha particle from its nucleus. The new nucleus formed has respectively, atomic number and mass number
A94 and 238
B90 and 236
C88 and 234
D90 and 234
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Question 2
waec2005
The mass of a proton is 1.0089\(\mu\) and that of a neutron is 1.0089\(\mu\). Determine the energy evolved in stabilizing the nucleus of nitrogen of mass number 14 with 7 protons and 7 neutrons. [speed of light = 3.0 x 108ms-1; 1\(\mu\) = 1.67 x 10-27kg]
A1.710 x 10-8J
B3.131 x 10-8J
C1.476 x 10-8J
D2.332 x 10-9J
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Question 3
waec2005
Light of energy 5.0 eV falls on a metal of work function 3.0 eV and electrons are emitted, determine the stopping potential. [electronic charge, e = 1.60 x 108ms-19]
A1.7V
B2.0V
C8.0V
D15.0V
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Question 4
waec2005
A process by which two light atoms join to form a new atom of higher atomic mass is
Anatural radioactivity
Bnuclear fission
Cnuclear fusion
Dchain reaction
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Question 5
waec2005
Beta particles are faster-moving
Aprotons
Belectrons
Cneutrons
Dphotons
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Question 6
waec2005
Which of the following statements is not a reason for using soft iron in making the core of a transformer? It
Aretains its magnetism for a long time
Bis easily magnitised
Creduces energy loss due to hysteresis
Dis easily demagnetised
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Question 7
waec2005
Which of the following statements is an advantage of nuclear fusion over nuclear fission?
AThe resulting chain reaction which produces large amount of energy
Bno radioactve wave is produced as bye product
Cvery high temperature is required in the process
Dthe end product is lead
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Question 8
waec2005
an electric motor is a machine that converts
Amechanical energy into electrical energy
Belectrical energy into mechanical energy
Chigh voltage to low voltage
Dlow voltage to high voltage
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Question 9
waec2005
A bar magnet is placed near and lying along the axis of a solenoid connected to a galvanometer. The pointer of the galvanometer shows no deflection when
Athe magnet is moved away from the stationary solenoid
Bthe solenoid is moved away from the stationary magnet
Cthe magnet is moved towards the stationary solenoid
Dthere is no relative motion between the magnet and the solenoid
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Question 10
waec2005
Lenz's law of electromagnetic induction states that
Aa force is exerted on a current-carrying conductor in a magnetic field
Belectromotive force id induced in a circuit whenever there is a change in the magnetic flux linked with the circuit
Cthe magnitude of the induced electromotive force in a circuit is proportional to the rate of change of flux linking the circuit
Dthe induced current in a coil is in such a direction that it sets up a magnetic field which opposes the change producing it
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Question 11
waec2005
The mass and weight of a body on earth are 8kg and 80N respectively. Determine the mass and weight of the body respectively on a planet where the pull of gravity is \(\frac{1}{8}\) that on earth
A8kg, 8N
B1kg, 10N
C64kg, 10N
D8kg, 10N
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Question 12
waec2005
A constantan wire has a cross sectional area of 4 x 10-8m2 and a resistivity of 1.1 x 10-6\(\Omega\)m. If a resistor of resistance 11\(\Omega\) is to be made from this wire, calculate the length of the wire required
A0.4m
B0.8m
C2.5m
D5.0m
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Question 13
waec2005
Which of the following statements explains lost volt in an electric circuit? The
Atotal p.d from a source to maintain a flow of current through the circuit as well as the source
Bp.d to drive current through the circuit component except the source
Cp.d across all external components connected to the source of electricity
Dp.d across the internal resistance of the cell
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Question 14
waec2005
An electric lamp is rated 240V, 40W. What is the cost of running the lamp for 72 hours if the electricity authority charges N2.50 per kWh?
AN7.20
BN18.00
C180.00
DN720.00
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Question 15
waec2005
a chemical cell of internal resistance 1\(\Omega\) supplies electric current to an external resistor of resistance 3\(\Omega\). Calculate the efficiency of the cell
A75%
B50%
C33%
D25%
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Question 16
waec2005
A parallel plate capacitor of capacitance 600\(\mu F\) has a potential difference of 200V between its plates. Calculate the charge on either plate of the capacitor
A1.2C
B3.3C
C3330.0C
D12.0000.0C
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Question 17
waec2005
A parallel plate capacitor of capacitance 600\(\mu F\) has a potential difference of 200V between its plates. Calculate the charge on either plate of the capacitor
A1.2C
B3.3C
C3330.0C
D12.0000.0C
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Question 18
waec2005
Two capacitors if capacitance 0.4\(\mu F\) and 0.5\(\mu F\) are connected in parallel and charged to a p.d. of 50V, Determine the total charge acquired
A45\(\mu C\)
B25\(\mu C\)
C20\(\mu C\)
D10\(\mu C\)
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Question 19
waec2005
The ability of a material to store an electric charge when its plates are at different potentials is referred to as its
Aconductance
Binductance
Ccapacitance
Dresistance
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Question 20
waec2005
In which of the following media is the transmission of sound wave fastest?
