An atom radiates 1.5 × 10-19J when an electron jumps from one level to another. What is the wavelength of the emitted radiation? (Planck’s constant 6.6 × l0-34Js ; Speed of light in vacuum = 3.0 × 108ms-1)
A1.32 × 10-6m
B2.97 × 10-6m
C3.30 × 10-6m
D6.82 × 10-6m
E8.01 × 10m-6
View Explanation & Discuss
Question 23
neco2005
491 K is equivalent to
A273 °C
B218 °C
C373 °C
D491 °C
E764 °C
View Explanation & Discuss
Question 24
neco2005
Which of the statements is/are true of two bodies involved in an inelastic collision? After collision.
I. the kinetic energy increases
II. The momentum decreases
III. Their velocities are the same.
AI only
BII Only
CIII only
DI and II only
EII and III only
View Explanation & Discuss
Question 25
neco2005
A body moves along a circular path with uniform angular speed of 0.6 rad s-1 and at a constant speed of 3.0 ms-1.
Calculate the acceleration of the body towards the centre of the circle.
A0.2.ms-2
B1.8 ms-2
C5.0 ms-2
D5.4 ms-2
E25.0 ms-2
View Explanation & Discuss
Question 26
neco2005
An object is placed in front of a concave mirror whose radius of curvature is 12cm. If the magnification of the Image produced is 1.5, how far is the object from the mirror?
A8cm
B10cm
C15cm
D18cm
E20cm
View Explanation & Discuss
Question 27
neco2005
The angle between the geographic and the magnetic meridians at a place on the earth’s surface is the
Aangle of declination
Bangle of depression
Cangle of dip.
Dlatitude of the place
Elongitude of the place
View Explanation & Discuss
Question 28
waec2005
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
View Explanation & Discuss
Question 29
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
View Explanation & Discuss
Question 30
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
View Explanation & Discuss
Question 31
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
View Explanation & Discuss
Question 32
waec2005
Beta particles are faster-moving
Aprotons
Belectrons
Cneutrons
Dphotons
View Explanation & Discuss
Question 33
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
View Explanation & Discuss
Question 34
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
View Explanation & Discuss
Question 35
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
View Explanation & Discuss
Question 36
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
View Explanation & Discuss
Question 37
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
View Explanation & Discuss
Question 38
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
View Explanation & Discuss
Question 39
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
View Explanation & Discuss
Question 40
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
