Question Library — KalmiPrep by Kalmitech

Physics WAEC / WASSCE 1998 Current Electricity & Electric Circuits

The diagram above illustrates a freely suspended bar magnet NS hanging from a point in a horizontal ceiling. The thread used for suspending the magnet and the axis of the magnet are as indicated on the diagram. The angle marked \(\theta\) is called the angle os

Attached Figure / Diagram

A

depression

B

declination

C

variation

D

elevation

E

dip

medium Difficulty

Physics WAEC / WASSCE 1998 Magnetism, Electromagnetism & AC Circuits

Lenz's law of electromagnet states that

A

the induced charge is constant for a fixed change of force

B

a force is exerted on a current-carrying conductor in a magnetic field

C

the magnitude of the induced e.m.f in a circuit is proportional to the rate of change of the number of lines of force linking the circuit

D

the induced current in a conductor is in such a direction as to oppose the change producing it

E

e.m.f. is induced in a circuit whenever there is a change in the magnetic flux linked with the circuit

medium Difficulty

Physics WAEC / WASSCE 1998 Magnetism, Electromagnetism & AC Circuits

A proton of charge 1.6 x 10\(^{19}\)C is projected into a uniform magnetic field of flux density 5.0 x 10\(^5\)T. If the proton moves parallel to the field with a constant speed of 1.6 x 10\(^6\)ms\(^{-1}\), calculate the magnitude of the force exerted on it by the field

A

0.0N

B

2.0 x 10-21N

C

1.3 x 10-17N

D

5.1 x 10-14N

E

2.3 x 1013N

medium Difficulty

Physics WAEC / WASSCE 1998 Current Electricity & Electric Circuits

An electron is accelerated from rest through a potential difference of 70kV in a vacuum. Calculate the maximum speed acquired by the electron (electronic charge = -1.6 x 10-19; mass of an electron = 9.1 x 10-31kg)

A

3.00 x 108ms-1

B

2.46 x 108ms-1

C

1.57 x 108ms-1

D

1.32 x 108ms-1

E

1.11 x 108ms-1

medium Difficulty

Physics WAEC / WASSCE 1998 Current Electricity & Electric Circuits

When light from a source is sent through a gas I. Certain wavelengths are absorbed. II. an emission line spectrum results. III. A dark line is left. Which of the following is/are correct?

A

i only

B

iii only

C

i and ii only

D

i and iii only

E

ii and iii only

medium Difficulty

Physics WAEC / WASSCE 1998 Units, Measurements & Dimensional Analysis

The diagram above represents a section of a pair of vernier calipers. The reading on the instrument is

Attached Figure / Diagram

A

5.22cm

B

5.24cm

C

5.26

D

5.35

medium Difficulty

Physics WAEC / WASSCE 1998 Newton's Laws, Momentum & Collisions

The process of increasing the energy of an atom via inelastic collision with an electron is known as

A

ionization

B

excitation

C

field emission

D

photoemission

E

thermonic emission

medium Difficulty

Physics WAEC / WASSCE 1998 Atomic, Quantum, Nuclear Physics & Electronics

A radioactive nuclide of proton number X emits a \(\beta\)-particle to form a new nuclide to proton number Y. The correct equation relating X and Y is

A

X = Y - 1

B

X = Y + 1

C

X = 1 - Y

D

X = \(\frac{1}{y}\)

E

X = Y

medium Difficulty

Physics WAEC / WASSCE 1998 Magnetism, Electromagnetism & AC Circuits

The direction of the magnetic field at a point in the vicinity of a bar magnetic is

A

along the line joining the point to the neutral point

B

always away from the south pole of the magnet

C

opposite the direction of theresultant field at that point

D

always towards the north pole of the magnet

E

the direction towards which the north pole of a compass needle would point

medium Difficulty

Physics WAEC / WASSCE 1998 Magnetism, Electromagnetism & AC Circuits

The diagram below illustrates an a.c.source of 50V(r.m.s.), \(\frac{100}{\pi}\)Hz connected in series with an inductor of inductor of inductance L and a resistor of resistance R. The current in the circuit is 2A and the p.d across L and R are 30V and 40V respectively. Calculate the power factor of the circuit

Attached Figure / Diagram

A

1.33

B

1.25

C

0.80

D

0.75

E

0.60

medium Difficulty

Physics WAEC / WASSCE 1998 Magnetism, Electromagnetism & AC Circuits

The diagram below illustrates an a.c.source of 50V(r.m.s.), \(\frac{100}{\pi}\)Hz connected in series with an inductor of inductor of inductance L and a resistor of resistance R. The current in the circuit is 2A and the p.d across L and R are 30V and 40V respectively. Calculate the average power dissipated in the circuit

Attached Figure / Diagram

A

100W

B

80W

C

60W

D

20W

E

10W

medium Difficulty

Physics WAEC / WASSCE 1998 Elasticity, Density, Pressure & Fluids

Use the following data to determine the length L of a wire when a fore of 30N is applied, assuming Hooke's law is obeyed \(\begin{array}{c|c}\text{Force applied/N} & 0 & 5 & 10 & 30\\ \hline \text{length of wire/mm} & 500.0 & 500.0 & 501.0 & L \end{array}\)

A

3.0mm

B

3.5mm

C

503.00mm

D

503.5mm

E

506.0mm

medium Difficulty

Physics WAEC / WASSCE 1998 Elasticity, Density, Pressure & Fluids

Which of the following explains the concave meniscus of water in a clean glass tube? the

A

adhension between water and glass molecules is greater than the sdhension between water molecules

B

cohension between water molecules is greater then the adhension between glass and water molecule

C

molecules of water near the glass move faster than the molecules at the centre of the tube

D

molecules of water at the water-air boundary are often attracted to the centre of the tube

E

weight of the water pulls the centre part of the surface down

medium Difficulty

Physics WAEC / WASSCE 1998 Elasticity, Density, Pressure & Fluids

The frictional effect between the layers of a moving fluid is called

A

capillarity

B

turbulence

C

diffusion

D

osmosis

E

viscosity

medium Difficulty

Physics WAEC / WASSCE 1998 Atomic, Quantum, Nuclear Physics & Electronics

Two radioactive elements X and Y have half-lives of 100 and 50 years respectively. Samples of X and Y initially contain equal number of atoms. What is the ratio of the number of the remaining atoms of X to that of Y after 200 years?

A

4:1

B

3:1

C

1:1

D

1:2

E

1:4

medium Difficulty