50 PHYSICS JAMB PAST QUESTIONS. LET TRY IT ✍️ ✍️ ✍️ CORRECTIONS WILL BE DROP LATER 📝 📝 1) When a ship sails from salt water into fresh water, the fraction of its volume above the water surface will A. increase B. decrease C. remain the same D. increase then decrease 2) I. Its velocity is constant II. No work is done on the body III. It has constant acceleration directed away from the centre IV. The centripetal force is directed towards the centre Which combination of the above is true of a body moving with constant speed in a circular track? A. II and IV B. I and IV C. II and III D. I and III 3) The velocity ratio of a machine is 5 and its efficiency is 75%. What effort would be needed to lift a load of 150N with the machine? A. 20N B. 30N C. 40N D. 50N 4) At a fixed point below a liquid surface, the pressure downwards is P1 and pressure upwards is P2. It can be deduced that? A. P1 > P2 B. P1 ≥ P2 C. P1 < P2 D. P1 = P2 5) If the force and the velocity on a system are each reduced simultaneously by half, the power of the system is A. doubled B. reduced to a quarter C. reduced by half D. constant 6) A catapult used to hold a stone of mass 500g is extended by 20cm with an applied force F. If the stone leaves with a velocity of 40m/s, the value of F is A. 4.0 x 102N B. 2.0 x 103N C. 4.0 x 103N D. 4.0 x 104N 7) A stream is flowing at 0.75ms−1 and a boat heading perpendicular for the stream landed at the opposite bank at an angle of 30°. Calculate the velocity of the boat. A. 1.50ms-1 B. 1.00ms-1 C. 0.86ms-1 D. 0.65ms-1 8) A rope is being used to pull a mass of 10kg vertically upward. Determine the tension in the rope if, starting from rest, the mass acquires a velocity of 4ms−1 in 8s [g = 10ms−2] A. 5N B. 50N C. 95N D. 105N 9) I. The frictional force is independent of the area of the surfaces in conduct II. The frictional force depends on the nature of the surfaces in contact III. The frictional force depends on the speed of sliding IV. The frictional force is directly proportional to the normal reaction. Which combination of the above is true of sliding friction? A. I, III and IV B. I, II and IV C. I, II and III D. II, III and IV 10) Total internal reflection occurs when light moves from? A. a dense medium to a less dense medium B. air to water C. water to glass D. a less dense to a dense medium 11) A quantity of water at 0°C is heated to about 30°C. At each degree rise in temperature, its density will A. rise steadily B. fall steadily C. fall then rise D. rise then fall 12) I. Coherence II. Same frequency III. Same wavelength IV. Same Intensity Which of the conditions above are necessary to produce interference fringes? A. I and III B. I, II and IV C. I, II and III D. II and III 13) A boy observes a piece of stone at the bottom of a river 6.0m deep. If he looks from the surface of the river, what is the apparent distance of the stone from him? [Refractive Index of Water = 4/3] A. 8.0m B. 5.5m C. 5.0m D. 4.5m 14) A thin wire with heavy weights attached to both ends is hung over a block of ice resting on two supports. If the wire cuts through the ice block while the block remains solid behind the wire, the process is called A. condensation B. sublimation C. regelation D. fusion 15) Dry Day 1 - 30°C | Day 2 - 29°C | Day 3 - 25°C Wet Day 1 - 22°C | Day 2 - 22°C | Day 3 - 21°C The reading above are for three consecutive days from a wet and dry bulb hygrometer. It can be concluded that the relative humidity for the three days A. decreased steadily B. remained unchanged C. increased steadily D. was least on Day 1 16) One end of a long wire is fixed while a vibrator is attached to the other end. When the vibrator is energized, the types of waves generated in the wire are A. stationary and longitudinal B. stationary and transverse C. progressive and transverse 17) A metal of mass 0.5kg is heated to 100°C and then transferred to a well-lagged calorimeter of heat capacity 80JK-1 containing water of heat capacity 420JK-1 at 15°C. If the final steady temperature of the mixture is 25°C, find the specific heat capacity of the metal. A. 877Jkg-1K-1 B. 286Jkg-1K-1 C. 133Jkg-1K-1 D. 92Jkg-1K-1 18) The main reason for making the cover of a vacuum flask airtight is to prevent heat loss by A. convection B. conduction C. radiation D. evaporation 19A radio is operated by eight cells each of e.m.f. 2.0V connected in series. If two of the cells are wrongly connected, the net e.m.f. of the radio is A. 8V B. 10V C. 12V D. 16V 20) If a charged ion goes through combined electric and magnetic fields, the resultant emergent velocity of the ion is A. E/B B. EB C. B/E D. E - B 21) A projection lantern is used to give the image of a slide on a screen. If the image is 24 times as large as the slide and the screen is 72.0m from the projecting lens, what is the position of the slide from the lens? A. 0.3m B. 3.0m C. 3.5m D. 4.0m 22) An electron of charge 1.6 x 10-19C and mass 9.1 x 10-31kg is accelerated between two metal plates with a velocity of 4 x 107ms-1, the potential difference between the plates is A. 4.55 x 103V B. 4.55 x 102V C. 9.10 x 101V D. 4.55 x 101V 23) A cell of internal resistance 0.01Ω can be measured accurately using the A. Ohm meter B. metre bridge C. potentiometer D. electroscope 24) What optical instrument can best be constructed with converging lenses of focal lengths 50cm and 5cm? A. Compound microscope B. Galileo's telescope C. Terrestrial telescope D. Astronomical telescope 25) in a pure semiconductor, the number of electrons in the conduction band is A. less than the number of holes in the valence band B. equal to the number of holes in the valence band C. greater than the number of holes in the valence band D. twice the number of holes in the valence band 26) In a thermonuclear reaction, the total initial mass is 5.02 x \(10^{-{2}{7}}\)kg and the total final mass is 5.01 x \(10^{-{2}{7}}\)kg. The energy released in the process is [c = 3.0 x \(10^8\) ms-1] A. 9.0 x 10-13J B. 9.0 x 10-12J C. 9.0 x 10-11J D. 9.0 x 10-10J 27) A gas would serve as an electrical conductor under A. reduced pressure and high current B. increased magnetic field C. reduced pressure and reduced potential D. exposure to visible light 28) An electric generator with a power output of 3.0KW at a voltage of 1.5KV distributes power along cables of resistance 20.0Ω. The power loss in the cables is A. 80.0W B. 40.0W C. 10.0W D. 0.1W 29) If the frequency of an emitted x-ray is 1.6 x 1016 Hz, the accelerating potential is? [e = 1.6 x 1019C, h = 6.63 x 10−34Js] A. 6630.0V B. 663.0V C. 66.3V D. 6.6V 30) If the fraction of the atoms of a radioactive material left after 120years is 1/64, what is the half-life of the material? A. 24 years B. 20 years C. 10 years D. 2 years 31) A certain radioactive source emits radiations that were found to be deflected by both magnetic and electric fields. The radiations are A. beta rays B. gamma rays C. x-rays D. unltr-violet rays 32) A 2H inductor has negligible resistance and is connected to a 50/π Hz A.C. Supply. The reactance of the inductor is A. 200 Ω B. 50 Ω C. 100/π Ω D. 25/π Ω 33) A cell of internal resistance 1Ω supplies current to an external resistor of 3Ω. The efficiency of the cell is A. 25% B. 33% C. 50% D. 75% 34) A conductor of length 2m carries a current of 0.8A while kept in a magnetic field of magnetic flux density 0.5T. The maximum force acting on it is A. 0.2N B. 0.8N C. 3.2N D. 8.0N 35) Light of energy 5eV falls on a metal of work function 3eV and electrons are liberated. The stopping potential is A. 1.7V B. 2.0V C. 8.0V D. 15.0V 36) The velocity y of a particle in a time t is given by the equation y = 10 + 2t2 Find the instantaneous acceleration after 5 seconds A. 60 ms-2 B. 20 ms-2 C. 15 ms-2 D. 10 ms-2 37) A simple pendulum has a period of 17.0s. When the length is shorten by 1.5m, its period is 8.5s. Calculate the original length of the pendulum A. 4.0 m B. 3.0 m C. 2.0 m D. 1.5 m 38) A sonometer wire is vibrating at frequency fo. If the tension in the wire is doubted while the length and the mass per unit length are kept constant, the new frequency of vibration is A. fo/2 B. 2fo C. fo/√2 D. fo√2 39) A travelling wave moving from left to right has an amplitude of 0.15m, a frequency of 550Hz and a wavelength of 0.01m. The equation describing the wave is A. y = 0.15 sin 200π(x - 5.5t) B. y = 0.15 sin π(0.01x - 5.5t) C. y = 0.15 sin 5.5π(x - 200t) D. y = 0.15 sin π(550x - 0.01t) 40) A transverse wave is applied to a string whose mass per unit length is 3 x 10-2kgm-1. If the string is under a tension 12N, the speed of the propagation of the wave is A. 5 ms-1 B. 20 ms-1 C. 30 ms-1 D. 40 ms-1 41) An engineer intends to deviate a light ray from its path by 120o through reflection from a plane mirror. Calculate the angle of incidence A. 60o B. 40o C. 30o D. 20o 42)The inner diameter of a test tube can be measured accurately using a? A. micrometer screw guage B. pair of dividers C. metre rule D. pair of vernier calipers 43)Two bodies have masses in the ratio 3:1. They experience forces which impart to them acceleration in the ratio 2:9 respectively. Find the ratio of forces the masses experienced. A. 1 : 4 B. 2 : 1 C. 2 : 3 D. 2 : 5 44)Particles of mass 10−2 kg is fixed to the tip of a fan blade which rotates with angular velocity of 100rad-1. If the radius of the blade is 0.2m, the centripetal force is A. 2 N B. 20 N C. 200 N D. 400 N 45)A lead bullet of mass 0.05kg is fired with a velocity of 200ms−1 into a lead block of mass 0.95kg. Given that the lead block can move freely, the final kinetic energy after impact is A. 50 J B. 100 J C. 150 J D. 200 J 46)A ball of mass 0.1kg is thrown vertically upwards with a speed of 10ms-1 from the top of a tower 10m high. Neglecting air resistance, its total energy just before hitting the ground is (take g = 10ms-2) A. 5 J B. 10 J C. 15 J D. 20 J 47)A car of mass 800kg attains a speed of 25m/s in 20 secs. The power developed in the engine is A. 1 . 25 x 104 W B. 2 . 50 x 104 W C. 1 . 25 x 106W D. 2 . 50 x 106 W 48)When the brakes in a car are applied, the frictional force force on the tyres is A. is a disadvantage because it is in the direction of the motion of the car B. is a disadvantage because it is in the opposite direction of the motion of the car C. is an advantage because it is in the direction of the motion of the car D. is an advantage because it is in the opposite direction of the motion of the car 49)If the stress on a wire is 107NM-2 and the wire is stretched from its original length of 10.00 cm to 10.05 cm. The young's modulus of the wire is A. 5 . 0 x 104 Nm-2 B. 5 . 0 x 105 Nm-2 C. 2 . 0 x 108 Nm-2 D. 2 . 0 x 109 Nm-2 50)A solid weigh 10 .00 N in air, 6 N when fully immersed in water and 7 . 0 N when fully immersed in a liquid X. Calculate the relative density of the liquid, X. A. 5/3 B. 4/3 C. 3/4 D. 7/10 EXAMSPEED ✍️✍️