JAMB UTME - Physics - 1998 | Green Bridge CBT

Question 1 Report

Electricity is supplied to a school along a cable of total resistance $0.5\,\Omega$ with the maximum current drawn from the mains as $100\text{ A}$. The maximum energy dissipated as heat for $1\text{ hr}$ is

3.6 x 103J

5.0 x 103J

3.0 x 105J

1.8 x 107J

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Question 2 Report

In photoelectric effect, electrons will leave the metal surface when illuminated by light of appropriate frequency if the photon energy is

greater than the work function

less than the work function

equal to the work function

equal to the maximium kinetic energy of the electron

Wave-particle Paradox

Structure Of The Atom (Nigeria Only)

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Question 3 Report

The physical properties of sound waves can best be described by

reflection and diffraction

polarization and reflection

polarization and diffraction

polarization and refraction

Reflection Of Light At Plane And Curved Surfaces

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Question 4 Report

In a resonance tube experiment, if the fundamental frequency of the vibrating air column is 280Hz, the frequency of the third overtone is

70Hz

840Hz

1120Hz

1960Hz

Electrostatics

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Question 5 Report

The linear expansivity of brass is 2 x 10-5C-1. If the volume of a piece of brass is 15.00cm3 at 00C, What is the volume at 100oC?

16.03cm3

16.00cm3

15.09cm3

15cm3

Answer Details

linear expansivity =

\frac{V_{2} - V_{1}}{V_{1} \times Δ θ}

3 x 2 x 10-5 = $\frac{V_{2} - 15}{15 \times (100 - 0)}$

V2 = 15.09cm3

Read lesson note on Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 6 Report

The velocity of a sound wave at 27oC is 360ms-1. Its velocity at 127oC is

120√3 ms-1

240 ms-1

240√3 ms-1

720√3 ms-1

Answer Details

Velocity

α \sqrt{t e m p e r a t u r e}

$\frac{V_{1}}{V_{2}} = \sqrt{\frac{T_{1}}{T_{2}}}$

therefore, $\frac{360}{V_{2}} = \sqrt{\frac{27 + 273}{127 + 273}}$

$V_{2} = 240 \sqrt{3}$ m/s

Read lesson note on Current Electricity (JAMB)

Current Electricity

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Question 7 Report

A uniform meter rule weighing 0.5N is to be pivoted on a knife-edge at the 30cm-mark. where will a force of 2N be placed from the pivot to balance the meter rule?

95cm

25cm

20cm

5cm

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Question 8 Report

A body on the ground is acted on by a force of 10N at a point P as shown in the fig above. What force is needed to stop the body from moving eastwards

5N in the direction of east

5N in the diretion of west

5V3N in the direction of west

10N in the southwest direction

Scalars And Vectors

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Question 9 Report

In a wheel and axle mechanism the diameters of the wheel and axle are 40cm and 8cm respectively. Given that the machine is 80% efficient, what effort is required to lift a load of 100N?

20N

25N

50N

80N

Answer Details

The wheel and axle mechanism is a simple machine used for lifting heavy loads. The mechanical advantage of a wheel and axle mechanism is given by the ratio of the radius of the wheel to the radius of the axle. In this case, the diameters of the wheel and axle are given, and so we need to calculate their radii. The radius of the wheel, r_w, is half the diameter of the wheel, so r_w = 20 cm. Similarly, the radius of the axle, r_a, is half the diameter of the axle, so r_a = 4 cm. The mechanical advantage of the wheel and axle mechanism is given by: MA = r_w / r_a Substituting the values we get: MA = 20 cm / 4 cm = 5 The efficiency of the machine is given as 80%, which means that 80% of the work put into the machine is used to lift the load. The remaining 20% is lost due to friction and other factors. Efficiency = (Output work / Input work) x 100% Since the output work is equal to the weight lifted (100 N) times the distance moved by the load, and the input work is equal to the effort required to lift the load times the distance moved by the effort, we can write: Efficiency = (100 N x d) / (E x d) x 100% where d is the distance moved by both the load and the effort. Simplifying this expression gives: Efficiency = 100 / MA Substituting the value of MA gives: 80% = 100 / 5 So, the effort required to lift a load of 100N is: E = (100 N x d) / (Output work) E = (100 N x d) / (Efficiency x Input work) Substituting the values of efficiency, output work and input work, we get: E = (100 N x d) / (0.8 x E x 5 x d) Simplifying this expression, we get: E = 25 N Therefore, the effort required to lift a load of 100N is 25N. Hence, the correct option is 25N.

Read lesson note on Pressure (JAMB)

Read lesson note on Simple Machines (JAMB)

Pressure

Simple Machines

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Question 10 Report

In a nuclear fusion experiment, the loss of mass amounts to 1.0 x 10-6kg. The amount of energy obtained from the fusion is

3.0 x 10-4J

3.0 x 10-1J

9.0 x 104J

9.0 x 1010J

Magnetic Field (Part 2)

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Question 11 Report

A bullet fired at a wooden block of thickness 0.15m manages to penetrate the block. If the mass of the bullet is 0.025kg and the average resisting force of the wood is 7.5 x 103N, calculate the speed of the bullet just before it hits the wooden block.

450ms-1

400ms-1

300ms-1

250ms-1

Current Electricity

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Question 12 Report

One valid assumption of the kinetic theory of gasses is the

the molecules of a gas are constantly in a state of motion and the number of collision remains constant

the number of molecule of gas increases with increasing pressure

as the temperature increases, the number of collision made by the gas molecule remains constant

the molecules of gas are all identical and are very small in size

Thermal Expansion

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Question 13 Report

The total resistance measured at PQ in the diagram above is

18.0Ω

11.0Ω

4.0Ω

2.0Ω

Current Electricity

Measurements And Units

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Question 14 Report

In a closed organ pipe producing a musical note, an antinode will always be produced at

the closed end

the open end

the middle

all the parts of the pipe

Temperature And Its Measurement

Propagation Of Sound Waves

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Question 15 Report

An object is placed in front of two plane mirrors inclined at an angle of $0^\circ$. If the total number of images formed is 7, Find the value of $\theta$

30o

45o

51o

90o

Answer Details

Number of image =

\frac{360}{θ}

-1

7 = $\frac{360}{θ}$ -1

thus, $θ$ = 45o

Read lesson note on Electrostatics (JAMB)

Electrostatics

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Question 16 Report

A 500W heater is used to heat 0.6kg of water from $25^\circ\mathrm{C}$ to $100^\circ\mathrm{C}$ in $t_2$ seconds. If another 1000W heater is used to heat 0.2kg of water from $10^\circ\mathrm{C}$ to $100^\circ\mathrm{C}$ in t, seconds, find $\frac{t_1}{t_2}$

50

5

5/4

1/5

Answer Details

Heat energy = Electrical energy

mc $θ$ = power x time

0.6 x c x (100 - 25) = 500 x t1

and, 0.2 x c x (100 - 10)= 100 x t2
$\frac{t_{1}}{t_{2}}$ = 5

Read lesson note on Heat Energy (WAEC)

Heat Energy

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Question 17 Report

A parallel plate capacitor has a common plate area of $5 \times 10^{-8}\,\mathrm{m}^2$ and plate separation of $2 \times 10^3\,\mathrm{m}$, Assuming free space, What is the capacitance? [$\epsilon_o = 9.0 \times 10^{-12}\,\mathrm{C}^2\mathrm{N}^{-1}\mathrm{m}^{-2}$]

2.25 x 10-17F

4.50 x 10-17F

2.25 x 10-16F

4.50 x 10-16F

Answer Details

C =

\frac{ε_{o} A}{d}

= $\frac{5 \times 10^{- 8} \times 10^{- 12} \times 9}{2 \times 10^{- 3}}$

= 22.5 x 10-17F

Read lesson note on Capacitors (JAMB)

Capacitors

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Question 18 Report

The most suitable type of mirror used for the construction of the search light is the

concave mirror

convex mirror

spherical mirror

parabolic mirror

Electrostatics

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Question 19 Report

A vapour is said to be saturated when

more molecules return to the liquid than the amount that left it

a dynamic equilibrium exists between the molecules of the liquid and the vapour molecules at a given temperature

the vapour pressure is equal to the atmospheric pressure

all molecules are moving with the same speed in all directions at a given temperature

Vapours

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Question 20 Report

A transformer which can produce 8V from a 240v a.c. supply, has an efficiency of 80%. If the current in the secondary coil is 15A, calculate the current in the primary coil.

0.625A

1.600A

2.500A

6.250A

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Question 21 Report

How many grams of water at 17oC must be added to 42g of ice at 0oC to melt the ice completely? [specific latent heat of fusion of ice = 3.4 x 105Jkg-1, specific heat capacity of water = 4200Jkg-1k-1]

200g

300g

320g

400g

Answer Details

Heat lost = Heat gained

mc $θ$ = mL

m x 4200 x 17 = 42 x 3.4 x 105

therefore, m = 200g

Read lesson note on Quantity Of Heat (JAMB)

Quantity Of Heat

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Question 22 Report

The force of repulsion between two point positive charges $5\,\mu\text{C}$ and $8\,\mu\text{C}$ separated at a distance of $0.02$ map art is. $\left[\dfrac{1}{4\pi\varepsilon_o}=9 \times 10^9\text{ Nm}^2\text{C}^{-2}\right]$

1.8 x 10-10N

9.0 x 10-8N

9.0 x 102N

4.5 x 103N

Answer Details

F =

\frac{1}{4 π ε_{o}}

x

\frac{q_{1} q_{2}}{r^{2}}

F = $\frac{5 \times 10 \times 8 \times 10}{0.002 \times 0.002}$ x 9 x 10

F = 900N

Read lesson note on Properties Of Waves: Reflection, Refraction, Diffraction (WAEC)

Properties Of Waves: Reflection, Refraction, Diffraction

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Question 23 Report

The displacement d produced in a glass block of thickness t and refractive index n when an object is viewed through it is

t – n

t (1 + 1/n)

t (1-1/n)

t (1/n - 1)

Refraction Of Light Through Plane And Curved Surfaces

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Question 24 Report

Which of the following can be used to reduce local action in a Laclanche cell?

A carbon rod as the positive pole

Pure zinc as the negative pole

Potassium permanganate solution in contact with the positive pole

common salt solution

Electric Cells

Conduction Of Electricity Through

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Question 25 Report

A man wears convex lens glasses of focal length 40cm in order to correct his eye defect. instead of the optimum 25cm, his least distance of distinct vision is

14cm

28cm

75cm

150cm

Answer Details

A person with an eye defect has difficulty seeing objects clearly, especially those that are close to them. The defect may be due to the shape of the eye, which prevents light from being focused correctly on the retina. A convex lens can be used to correct this defect by converging the light before it enters the eye, thus allowing the eye to focus the image correctly. The focal length of a lens is a measure of its ability to converge light. A lens with a shorter focal length is more powerful and can converge light more strongly than a lens with a longer focal length. For a person with an eye defect, the focal length of the lens must be chosen to compensate for the defect and provide the correct amount of convergence. In this question, the man wears convex lens glasses with a focal length of 40cm to correct his eye defect. However, his least distance of distinct vision is not the optimum distance of 25cm. The least distance of distinct vision is the minimum distance at which an object can be seen clearly. To find the least distance of distinct vision for this man, we can use the lens equation: 1/f = 1/di + 1/do Where f is the focal length of the lens, di is the distance of the image from the lens, and do is the distance of the object from the lens. For the man to see an object at his least distance of distinct vision, the image formed by the lens must be at infinity (di = infinity). Plugging these values into the lens equation and solving for do gives: 1/40 = 1/infinity + 1/do 1/do = 1/40 do = 40cm Therefore, the man's least distance of distinct vision is 40cm. The correct answer to the question is "150cm," which is not among the answer options provided.

Read lesson note on Electric Field (WAEC)

Electric Field

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Question 26 Report

Which of these statements are correct for the pressures in liquids? i. pressure in a liquid at a point acts equally in all directions. ii. pressure increases with depth. iii. pressure at a depth depends on the shape of the container. iv. pressure at the same depth in different liquids are proportional to the density at different liquids.

i, ii, iii only

i, ii, iv only

i, iii, iv only

ii, iii, iv only

Temperature And Its Measurement

Pressure

Liquids At Rest

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Question 27 Report

A parachute attains a terminal velocity when

its density is equal to the density of air

the viscous force of the air and the upthrust completely counteract its weight

it expands as a result of reduced external pressure

the viscous force of the air is equal to the sum of the weight and upthrust

Equilibrium Of Forces

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Question 28 Report

A platinum resistance thermometer records $3.0\,\Omega$ at $0^\circ\mathrm{C}$ and $8.0\,\Omega$ at $100^\circ\mathrm{C}$. If it records $6.0\,\Omega$ in a certain environment, The temperature of the medium is

80oC

60oC

50oC

30oC

Answer Details

8

Ω

.....100oC

6 $Ω$ ..... $θ$ oC

3 $Ω$ .....0oC

$\frac{6 - 3}{8 - 3}$ = $\frac{θ - 0}{100 - 0}$

therefore, $θ$ = 60oC

Read lesson note on Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 29 Report

The tendon in a man's leg is 0.01m long. If a force of 5N stretches the tendon by 2.0 x 10-5m, calculate the strain on the muscle.

5 x 106

5 x 102

2 x 10-3

2 x 10-7

Elasticity

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Question 30 Report

The force of attraction between two point masses is 10-4N when the distance between them is 0.18m. If the distance is reduced to 0.06m, calculate the force.

1.1 x 10-5N

3.3 x 10-5N

3.0 x 10-4N

9.0 x 10-4N

Gravitational Field

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Question 31 Report

A man whose mass is 80kg climbs a staircase in 20s and expends power of 120W. Find the height of the staircase.[g = 10ms-2]

1.8m

2.0m

2.5m

3.0m

Work, Energy And Power

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Question 32 Report

A ball is moving at 18ms-1 in a direction inclined at 60o to the horizontal. The horizontal component to its velocity is

9√3ms-1 ·

6√3ms-1 ·

8√3ms-1 ·

9ms-1

Motion

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Question 33 Report

The atmospheric pressure due to water is 1.3 x 106Nm-2. What is the total pressure at the bottom of an ocean 10m deep? [Density of water = 1000kgm-3, g = 10ms-2]

1.3 x 107Nm-2

1.4 x 106Nm-2

1.4 x 105Nm-2

1.0 x 10 5Nm-2

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Question 34 Report

An object 0 lies at a distance m in front of concave mirror of focal length f. If m < f, then the final image obtained will be

virtual and diminished

magnified and erect

real and inverted

diminished and erect

Electrostatics

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Question 35 Report

An ebonite rod rubbed with fur attracts a glass rod rubbed with silk because

ebonite has a negative charge while glass has a positive charge

ebonite has a positive charge while glass has a negative charge

both have negative charges

both have positive charges

Electrostatics

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Question 36 Report

The electrochemical equivalent of a metal is 1.3 x 10-7kgC-1. The mass of the metal which 2.0 x 104C of electricity will deposit from a suitable electrolyte is

6.5 x 10-2kg

2.6 x 10-2kg

6.5 x 10-3kg

2.6 x 10-3kg

Electric Cells

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Question 37 Report

In the AC circuit diagram above, the resonance frequency is

5000π Hz

2500π Hz

5000/π Hz

2500/π Hz

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Question 38 Report

In free fall, a body of mass 1kg drops from a height of 125m from rest in 5s. How long will it take another body of mass 2kg to fall from rest from the same height? [g = 10ms-1·]

5s

10s

12s

15s

Motion

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Question 39 Report

A steel wire of length 0.50m is stretched between two fixed points and its fundamental frequency is 200Hz. The speed of the wave in the wire is

100ms-1

120ms-1

200ms-1

250ms-1

Measurements And Units

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Question 40 Report

A solid of weight 0.600N is totally immersed in oil and water respectively. If the upthrust of oil is 0.210N and the relative density of oil is 0.875. Find the upthrust in water.

0.600N

0.360N

0.240N

0.180N

Answer Details

Rd =

\frac{upthrust in oil}{upthrust in H_{2} O}

thus; 0.875 = $\frac{0.21}{upthrust in H_{2} O}$

upthrust in H2O = 0.24N

Read lesson note on Gravitational Field (JAMB)

Gravitational Field

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Question 41 Report

The physical quantity that has the same dimensions as impulse is

energy

momentum

surface tension

pressure

Work, Energy And Power

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Question 42 Report

Which of the following are true about the infra-red radiation? i. it is invisible ii. it is called heat ray iii. its frequency is higher than that of blue light iv. it travels as a transverse wave

i, ii, iii and iv

i, ii, iv only

i, iii, iv only

ii, iii, iv only

Electromagnetic Waves: Types Of Radiation In Electromagnetic Spectrum

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Question 43 Report

A ball of mass 0.15kg is kicked against a rigid vertical wall with a horizontal velocity of 50ms-1. If it rebounced with a horizontal velocity of 30ms-1, Calculate the impulse of the ball on the ball · ·

3.0Ns

4.5Ns

7.5Ns

12.0Ns