1. How many types of units exist in physics?
A. 3
B. 7
C. 2 ✔️
D. 225
2. What is the dimensional formula of power ?
A. ML⁻² T⁻³
B. ML² T³
C. M²L T⁻³
D. ML² T⁻³ ✔️
3. Plank's constant is measured in
A. Joule/Hertz ²
B. Kgm²/s²
C. Joule
D. Kgm²s–¹ ✔️
4. The dimensions of Kinetic energy is same as that of
A. Force
B. Pressure
C. Work ✔️
D. Momentum
5. Which of the following physical quantities is different from others?
A. Work
B. Kinetic energy
C. Force ✔️
D. Potential energy
6. A physical quantity which can be completely described by its magnitude only is called
A.scalar ✔️
B. vector
C. displacement
D. velocity
7. Which of the following quantities are vectors?
A. speed, velocity, acceleration
B. velocity, acceleration, force ✔️
C. force, acceleration, mass
D. length, mass, time
8. Which of the following physical quantities has the same unit as that of potential difference?
A. Electric field
B. Electric current
C. Electromotive force ✔️
D. Stress
9. The value of permittivity of free space is given by
A. 8.854 x 10–⁹ F/m
B. 8.854 x 10–¹⁰ F/m
C. 8.854 x 10–¹¹ F/m
D. 8.854 x 10–² F/m ✔️
10. Air conditioners are good example of
A. conduction
B. convection ✔️
C. radiation
D. conduction and radiation
11. If the displacement of an object is proportional to square of time, then the object moves with:
A. Uniform velocity
B. Uniform acceleration ✔️
C. Increasing acceleration
D. Decreasing acceleration
12. Suppose a boy is enjoying a ride on a marry-go-round which is moving with a constant speed of 10 m/s. It implies that the boy is:
A. At rest
B. Moving with no acceleration
C. In accelerated motion✔️
D. Moving with uniform velocity
13. Which of the following can sometimes be ‘zero’ for a moving body?
i. Average velocity
ii. Distance travelled
iii. Average speed
iv. Displacement
A. Only (i)
B. (i) and (ii)
C. (i) and (iv) ✔️
D. Only (iv)
14. A car travels 90 m due North in 15 s. Then the car turns around and travels 40 m due South. What is the magnitude and direction of the car's resultant displacement?
A. 40 metres, South
B. 50 metres, South
C. 50 metres, North✔️
D. 40 metres, North
15. When a car driver travelling at a speed of 10 m/s applies brakes and brings the car to rest in 20 s, then the retardation will be:
A. + 2 m/s²
B. − 2 m/s²
C. − 0.5 m/s² ✔️
D. + 0.5 m/s2
16. Wooden ladles are used to stir or scoop hot soup because of it's
A. good conduction of heat
B. good conduction of electricity
C. good insulation of electricity
D. good insulation of heat ✔️
17. A force required just to prevent a body sliding down a rough inclined plane of angle 45⁰ and coefficient of friction 0.6 is F. The minimum force required to move the body up the plane is
A. 1.6 F ✔️
B. 4 F
C. 6.2 F
D. 3 F
18. Shadows and eclipses result from the
A. refraction of light
B. rectilinear propagation of light ✔️
C. defraction of light
D. reflection of light
19. An object which is 3cm high is placed vertically 10cm in front of a concave mirror. If this object produces an image 40cm from the mirror, the height of the image is
A. 0.75cm
B. 4.00cm
C. 8.00cm
D. 12.00cm ✔️
20. The maximum efficiency of a machine
A. is directly proportional to the velocity ratio
B. should occur when the load is 50% of maximum permissible load
C. is given by mechanical advantage divided by velocity ratio ✔️
D. is given by velocity ratio divided by mechanical advantage
21. The resultant of two given vectors is maximum when..
A. the vectors are acting in the opposite direction
B. both the vectors are acting in the same direction ✔️
C. the vectors are at right angles
D. the vectors are parallel to each other
22. The resultant of two given vectors is maximum when the angle between them is
A. 90⁰
B. 45⁰
C. 30⁰
D. 0⁰ ✔️
23. If the velocity of a body is doubled its kinetic energy is
A. also doubled
B. halved
C. 1/4 th
D. is 4 times ✔️
24. The base of an electric iron is brightly polished mainly
A. to make it smooth and frictionless
B. to make it rust-proof
C. to reduce heat loss by conduction
D. to reduce heat loss by radiation ✔️
25. A perpendicular force is applied to a certain area and produces a pressure P. If the same force is applied to a twice bigger area, the new pressure on the surface is:
A. 4P
B. 2P
C. P/4
D. P/2 ✔️
26. A normal force of 200N acts on an area of 0.02m².Find the pressure in pascal.
A.100 Pascal
B. 10,000 Pascal ✔️
C. 200 Pascal
D. 10⁵ Pascal
27. In a spaceship, objects revolving around the Earth appears to be
A. small
B. large
C. weightless ✔️
D. massive
28. The most notable difference between a radio wave and a light wave is
A. speed.
B. refractive index.
C. reflectivity.
D. frequency ✔️
29. In optics an object which has higher refractive index is called
A. Optically rarer
B. Optically
C. Optical denser ✔️
D Refractive index
30. An object with a higher surface area would
A. emit and absorb more infrared radiations ✔️
B. emit more but absorb less infrared radiations
C. emit less but absorb more infrared radiations
D. emit and absorb less infrared radiations
31. What will be the magnitude of e.m.f. induced in a 200 turns coil with cross section area 0.16 m² if the magnetic field through the coil changes from 0.10 Wb m–² to 0.30Wb m–² in 0.05 s ?
A. 128 V ✔️
B. 130 V
C. 118 V
D. 132 V
32. An artificial satellite of the earth releases a packet. If air resistance is neglected, the point where the packet will hit,
A. Bemudal Triangle
B. Centre of the Earth
C. Greenwich London
D. The packet will never reach the Earth 🌎 ✔️
33. The displacement of a particle performing simple harmonic motion is given by,x= 8 sinωt + 6 cosωt, where distance is in cm and time is in second. The amplitude of motion is
A. 10 cm ✔️
B. 14 cm
C. 2 cm
D. 3.5 cm
34. In transformer, alternating current is induced in
A. primary coil
B. secondary coil✔️
C. iron core
D. resistor
35 . If a secondary coil has 40 turns, and, a primary coil with 20 turns is charged with 50 V of potential difference, then the potential difference in the secondary coil would be
A. 50 V
B. 25 V
C. 60 V
D. 100 V ✔️
36. A simple pendulum on length l and mass m is suspended vertically. The string makes an angle θ with the vertical. The restoring force acting on the pendulum is
A. mg tanθ
B. mg sinθ
C. – mg sinθ ✔️
D. – mg cosθ
37. A radioactive source has a half-life of 80s. How long will it take for 7/8 of the source to decay? [1 mark]
A. 10 s
B. 70 s
C. 240 s ✔️
D. 640 s
38. A radioisotope has half life of 10 years. What percentage of the original amount of it would you accept to remain after 20 years ?
A. 1.5 %
B. 2.5 %
C. 0.5 %
D. 25 % ✔️
39. A milliammeter of resistance of 5 ohms gives a full-scale deflection for a current of 15 mA. If the milliammeter is to be used to measure a current up to 1.5 A the size of the resistance that must be attached to the milliammeter is
A. 0.0505 ohm
B. 0.505 ohm
C. 0.05 ohm✔️
D. 505 ohm
40. Determine the total electric flux of a unit positive charge which is kept in the air?
A. ϵ₀⁻¹ ✔️
B. ϵ₀
C. 4πϵ₀
D. 4πϵ₀⁻
▪️DESCRIPTIVE SOLUTIONS:
N/B: Only selected Questions will be solved, if you have any concerns outside this, Please let us know”
1) Two types of Units are recognised in Physics.
•Fundamental and derived Units•
2) Dimensional formular of Power.
Power = Energy /Time
Let's use P.E to derive our energy.
P.E = m × g × h
P.E = kg × m/s² × m
P.E = kg m²/s²
Mass(kg) = M
meter (m) = L
Time(s) = T
P.E = ML²T-²
Power = ML²T-² /T
Power = ML²T-³
▪️Method B✍️
2) Power = work done/time taken
= Force × distance
----------------------
Time
= Kgms-² × m
----------------
s
= Kgm²s-³ = ML²T-³
3) Energy = hf
Where h = Planck constant
Therefore Planck constant = Energy/frequency
= Force × distance
---------------------
Frequency
Frequency is the inverse of time
Therefore Planck constant = Energy × time
= Kgms-² × m × s
=Kgm²s-¹
5) All are Scalar quantities except “Force”
Force is a vector quantity (having magnitude and direction).
11) S = ut + 1/2 at²
S is directly proportional to t²
(1/2 is constant)
This is only possible in uniformly accelerated motion
12) This is illustrated in circular motion..
Uniform speed but varying direction..
Speed is uniform because it's a scalar quantity defined by only magnitude but not direction.
Velocity however, is not uniform because of the varying direction of the merry go round.
The boy also undergoes acceleration because of the varying direction” which lead to a “varying velocity.
13). Displacement can sometimes be zero for a body in motion.
If I leave my house and return to it.
I've travelled some distance but no -displacement- from my initial position which is “my house”
In the absence of displacement.
Average velocity is bound to be “zero”
14) The car simply 90km North and travelled backwards which is towards the south..
But it didn't travel up to 90m get to the equator.
90-40 = 50meters, North
It's still on the North Side
15) a = V-U/t
U= 10m/s
V= 0m/s
Time = 20s
a = 0-10/20
a= -0.5m/s²
17) The force required to prevent it from sliding downwards is equal to it's weight.
-Only under this condition can the body remain at rest;
But in moving the body up the plane.
We'll have to overcome weight and the force of friction.
This is because force of friction is now acting downwards alongside the weight.
Minimum force = Mgsin45 + U (mgcos45)
Sin 45 = Cos 45
Mgsin 45 = Mgcos 45
Minimum Force = F + 0.6 (F)
Minimum Force = 1.6F
19)
Image height(IH) = ?
Object height (OH) = 3cm
Object distance (U) = 10cm
Image distance (V) = 40cm
IH/OH = V/U
IH/ 3 = 40/10
IH = 3 × 40/10
IH = 12cm
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