221.Which of the statements below are correct about threshold wavelength of metal: (1) Increases with frequency of light (2) Decrease with frequency of light (3) Increases with light intensity
- A. 1 only
- B. 2 only
- C. 3 only
- D. 1, 2 and 3 only
222.A ball is projected from the ground at an angle of 30⁰ with the horizontal at an initial speed of 40ms⁻¹ Ignoring air friction. Calculate the time it will take the ball to strike the ground (acceleration due to gravity g = 10ms⁻¹).
223.A copper cube weights 0.25N in air, 0.17N when completely immersed in paraffin oil and 0.15N when completely immersed in water. The ratio of upthrust in oil to upthrust in water is
- A. 3:5
- B. 4:5
- C. 7:10
- D. 13:10
224.Find the frequencies of the first three harmonics of a piano string of length 1.5m, if the velocity of the waves on the string is 120ms⁻¹.
- A. 180Hz, 360Hz, 540Hz.
- B. 360Hz, 180Hz, 90Hz.
- C. 40Hz, 80Hz, 120Hz.
- D. 80Hz, 160Hz, 240Hz
225.The type of radiation that does not have effect with electric or magnetic field is
- A. Gamma rays
- B. Beta particles
- C. Alpha particles
- D. Hydrogen
226.The electromagnetic radiation with the strongest penetrating power is
- A. Caesium
- B. Beta particles
- C. Alpha particles
- D. Gamma rays
227.A ball is dropped from a roof at the same time as another ball is thrown upward from the roof.
- A. Have the same velocity when they reach the ground
- B. Have the same acceleration when they reach the ground
- C. Reach the ground at the same time
- D. Reach the ground at the same time
228.Which of the following particles is more strongly affected by magnetic field
- A. Alpha
- B. Beta
- C. Gamma
- D. X-rays
229.A stone thrown upward has an acceleration that is
- A. Smaller than that of a stone thrown downward
- B. The same as that of the stone thrown downward
- C. Greater than that of a stone thrown downward
- D. Zero until it reaches the highest point in its path
230.A car towing a trailer is accelerating on a level road. The car exerts a force on the trailer whose magnitude is
- A. The same as that of the force the trailer exerts on the car
- B. The same as that of the force the trailer exerts on the road
- C. The same as that of the force the road exerts on the trailer
- D. Greater than that of the force the trailer exerts on the car
231.The resultant of two forces acting on an object is maximum if the angle between them is
232.How long a bicycle with an acceleration of 0.8m/s² take to go from 4 to 12ms⁻²
- A. 6.4s
- B. 10s
- C. 15s
- D. 26s
233.A household refrigerator consumes electrical energy at the rate of 200W, if the electricity costs 5k per kWh; calculate the cost(in naira) of operating the appliance for 30days
- A. 7.20
- B. 12.00
- C. 30.00
- D. 33.33
234.A stone of mass 1kg is dropped from a height of 10m above the ground and falls freely under gravity. Its kinetic energy 5m above the ground is then equal to
- A. its kinetic energy on the ground
- B. half its initial potential energy
- C. its initial potential energy.
- D. twice its initial potential energy.
235.The resistivity of a metal such as copper increase with increasing temperature because
- A. The conduction electrons make more frequent collisions with each other
- B. the conduction electrons make more frequent collisions with the atoms of the metal
- C. The metal expands and offers more resistance to the flow of electrons
- D. It is more difficult to cause electrons to leave their parent atom
236.For which of the under listed quantities is the derived ML²T² correct? i.Momentofaforce ii.Work iii.Acceleration
- A. I only
- B. II only
- C. III only
- D. I and II
237.A force of 200N acts at an angle of 140⁰ with respect to the positive x-direction. What are the components of this force in the x and y direction.
- A. -1540N, 1280N
- B. -1500N, 2010N
- C. -1280N, 1540N
- D. -1450N, 1200N
238.A proton charge 1.6x10⁻¹⁹C is projected into a uniform magnetic field of flux density 5.0 x 10⁻⁵T. If the proton moves parallel to the field with a constant speed of 1.6 x 10⁵ms⁻¹. Calculate the magnitude of the force exerted by the field.
- A. 0.0N
- B. 2.0x10⁻²³N
- C. 1.3x10⁻¹⁸N
- D. 5.1x10⁻¹⁴N
239.A radio active nuclide of proton number X emits a β particle to form a new nuclide of proton number Y. The correct equation relating X and Y is
- A. X=Y–1
- B. X=Y+1
- C. X=1–Y
- D. X=1/Y