2021 JAMB: Physics Yearly Repeated Top 40 Questions And Answers

2021 JAMB: Physics Yearly Repeated Top 40 Questions And Answers

1 :- the velocity ratio of an inclined plane is CORRECT ANSWER = 1/sinQ

2 :- where must an object be placed in front of the concave mirror so that the image will formed between the centre of curvature and the focus CORRECT ANSWER = beyond the centre 3 :- optical instruments do NOT employ the principle of linear magnification in their operations rather they use CORRECT ANSWER = angular magnification

4 :- the force of attraction between two masses m1 and m2 separated at a distance 2r is given as CORRECT ANSWER = Gm1 m2/4r2

5 :- the condition for resonance to occur in an R-L-C serves circuit is CORRECT ANSWER = W0 = 1/Lc 6 :- calculate the work done if a force of 10N applied at an angle of 30 0 to the horizontal moves the body through a distance of 0.05m CORRECT ANSWER = 0.25 {3 J

7 :- the expression for electric potential (V) is CORRECT ANSWER = (q / 4Er)

8 :- a solid weighs 10.5N in air and weighs 5.5N when immersed in a liquid of density 900kgm-3, calculate the volume of the solid CORRECT ANSWER = 5.56 x 10 -4 m 3

9 :- during dispersion, colours of light CORRECT ANSWER = travel at different speeds 10 :- cobvert 180 0F to 0C CORRECT ANSWER = 82 0C

11 :- the bean balance is used to measure CORRECT ANSWER = mass

12 :- the diagram above represents four identical beaker of water with some droplet of a blue colour pigment. Which of them will have a faster rate of diffusion? CORRECT ANSWER = beaker IV

13 :- a thick glass tumbler cracks when hot water is pour into it because of CORRECT ANSWER = uneven expansion

14 :- the point M in the diagram above is in stable equilibrium with CORRECT ANSWER = minimum potention energy 15 :- the charge stored by a 5F capacitor connected to a potential difference of 40V is CORRECT ANSWER = 200C

16 :- the dissociation of salt solution and acids into ions is known as CORRECT ANSWER = electroysis

17 :- the resultant of two parallel forces acting in the same direction applied to a block of wood will be CORRECT ANSWER = maximum

18 :- from the above the induced e.m.f depends on CORRECT ANSWER = I, II and III 19 :- how much current does a 120W light bulb draw when connected to a voltage of 240? CORRECT ANSWER = 0.5A

20 :- from the above diagram the effective resistance between P and Q is CORRECT ANSWER = 4.33n

21 :- a semi-conductor with rqual numver of holes and electron is known as CORRECT ANSWER = intrinsic semi-conductor

22 :- which of the following is CORRECT about the motion of a simple pendulum? CORRECT ANSWER = potention energy is maximum at the extremes

23 :- in the vibration of stretched strings, the frequency F and the tension T are related by CORRECT ANSWER = f & square root T) 24 :- from the diagram above, the pressure acting on the trapped air is CORRECT ANSWER = H mmHg

25 :- light energy E is expressed as CORRECT ANSWER = E = hf

26 :- the ejection of electron from the surface of a CORRECT ANSWER = thermianic emission

27 :- where does refraction take place? CORRECT ANSWER = at the boundary between

28 :- ten 6V cells connected in parallel will give an effective e.m.f of CORRECT ANSWER = 6V 29 :- vavpour is said to be saturated when CORRECT ANSWER = in a dynamic equilibrium

30 :- a lagged calculator is suitable for measuring heat energy because it CORRECT ANSWER = prevents heat loss and gain

31 :- a wire carries a current of 3.0A with a magnetic field 2.0T at an angle of 30 0. calculate the force on a segment of wire 0.5m CORRECT ANSWER = 1.5N

32 :- which method of heat transfer is electro-mamgnetic in nature? CORRECT ANSWER = radiation

33 :- a light of 6.22eV is incident on a cadmium surface. If a stopping voltage of 2.15eV is required to reduce the photocurrent to zero, calculate the work function of cadmium CORRECT ANSWER = 34 :- from the digram above, calculate F CORRECT ANSWER = 60.00N

35 :- which of the folowing exhibits a wave motion? CORRECT ANSWER = a plucked stretched s tring

36 :- a stone weighs W1 Newton in air W2 Newton in water. The relative density of the stone is CORRECT ANSWER = W1/(W1-W2)

37 :- why do pressure pots cook food faster than other conventional pots? CORRECT ANSWER = its higher pressure

38 :- a spring of length 0.06m is acted upon by a force of 2N creating an extension of 0.02m. What would be the length when the applied force is increased by 8N? CORRECT ANSWER = 0.14m

39 :- when a bar magnet is suspended freely in the earth’s magnetic field, it will point to CORRECT ANSWER = north – south direction 40 :- the point where a ball moving in a viscous liquid start to move with uniform velocity is CORRECT ANSWER = terminal velocity