# JAMB 2019 physics questions and answers

Subject: Physics

Date: 11th April 2019

Time: 7:00 AM

1. the purpose of the vacuum in a thermos flask is to reduce the loss or gain heat by
Ans. convection

2. the body which emits light itself is
Ans. a luminous body

3. calculate the frictional force acting on a 20kg mass on a horizontal floor if the coefficient between the surface is 0.5 (g = 10m -2)
Ans. 100N

4. given the radius of the earth to be 6.4 x 10 6m. What velocity would a space agency consider to put a satellite in orbit?
Ans. 11.300ms -1

5. an electron of charge 1.6 x10 -19 C moves at a right angle to the magnetic field of intensity 2.0 x 10 -4T. If the speed of the electron is 1.5 x 10 3 ms-1. calculate the force acting on the charge
Ans. 4.8 x 10 -5N

6. the two processes that are essential in an air conditioning system are
Ans. evaporation and condensation

7. if atmosphere n pressure is taken to be 1.3 x 10 6Nm -2, the pressure at the swimming pool 200m deep is (g = 10ms -2, the density of water = 10 3 kgm-3)
Ans. 3.3 x 10 6Nm -2

8. calculate the spring constant when a force of 10N applied on a spring produced an extension of 0.05m
Ans. 200Nm -1

9. 0.1kg of steam at 100 0C condenses to water at 100 0C. If the specific latent heat vaporization of water is 2.2 x 10 6jkg -1, the amount of heat given up is
Ans. 2.2 x 10 5 J

9. 0.1kg of steam at 100 0C condenses to water at 100 0C. If the specific latent heat vaporization of water is 2.2 x 10 6jkg -1, the amount of heat given up is
Ans. 2.2 x 10 5 J

10. an electric iron rated 200W is used for 5hrs. Calculate the cost of using the iron if the cost of electrical energy is N5.00 per kWh
Ans. N5.00

11. which of the following radiation has the highest penetrating power?
Ans. gamma rays

12. the power of a convex lens of focal length 20cm is
Ans. 5D

13. a lift of mass 1000kg lifts up 10 people with total masses 650kg to a height of 40m In 50s. Calculate the power of the lift
Ans. 132,000W

14. if the length of air column in a closed pipe at which the first resonance was observed is 0.425m, what is the wavelength of the air column?
Ans. 1.70m

15. what principle is the bean balance based on?
Ans. principle of the moment are equilibrium

16. where will an object be placed in front of a concave mirror to have an image which is magnified, upright and virtual?
Ans. between the mirror

17. which of the following is an example of a secondary cell?
Ans. voltaic cell

18. when white light is dispersed, the component of the visible spectrum having the longest wavelength is
Ans. red

19. which of the following statements is correct when an alternating current circuit resonates?
Ans. XL = Xc

19. which of the following statements is correct when an alternating current circuit resonates?
Ans. XL = Xc

20. from b the diagram above, a boat cruised due east and changes its direction 60 0 north east before it encountered an engine failure. Calculate the shortest distance of a rescue boat from the same point of departure.
Ans. 67.66m

21. which of the statement above define the velocity ratio of a machine?
Ans. I, II and IV

22. a stone weights N in air 2 in water. Calculate the relative density of the stone.
Ans. w1/(w1-w2)

23. a pin is placed at the bottom of water, if when viewed directly above the water it is displaced by 3cm, calculate the thickness of the water
Ans. 4cm

24. the diagram above shows am an electric circuit. If the key is closed the voltmeter V reads the
Ans. terminal voltage

25. the minimum distance between a sound and a reflector for an echo to be heard in a second is (velocity of sound in air = 340 -1)
Ans. 170m

26. the isotope which decays by emission to produce
Ans. 111 48 Y

27. the temperature -273 0C is called the
Ans. absolute zero of temperature

28. from the diagram above, calculate the moment of the force of 40N about the point O
Ans. 120Nm

29. the magnetic elements that determine the earth’s magnetic field at a place are given below except
Ans. electric induction

30. from the digram above, calculate the equivalent capacitor
Ans. 2F

31. if a charge of 60 C experience a force of 12N, calculate the electric intensity
Ans. 2.0 x 105 Ac -1

32. the major carriers in a p-type semiconductor material are
Ans. holes

33. a certain box has a length of 90cm at 30 0 and 90.1cm at 530 0C. Calculate the coefficient of superficial expansion
Ans. 4.4 x 10 -6 K -1

34. the absorption of ink by blotting paper involves
Ans. capillary action

35. which of the following has the largest heat capacity
Ans. 10kj of water

36. from the above d iagram, a hunter threw a spear at 45% to kill an antelope. What is R?
Ans. maximum range

37. which of the following is NOT part of a.d.c generator?
Ans. slip rings

38. all of the following indicates thermometric properties except
Ans. change in mass

39. 60 waves passthrough a point in a ripple tank in 30s. The frequency of the wave is
Ans. 2Hz

40. find the mass of copper deposited on the cathode of copper voltameter if a current of 1.5A passes through it for 900s. (e.c.e of copper = 3.3 x 10 -2kgC -1)
Ans. 4.5 x 10 -4kg

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• March 14, 2020 at 2:28 pm