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WAEC SSCE - Physics - 2022 (Objective)

Ibeere 1 Ìròyìn

Suppose three identical steel balls Q, R, and S, are placed on an undulating ground as illustrated in the diagram above. Which of the balls is/are in neutral equilibrium?

S only

Q only

R only

Q and S only

Awọn alaye Idahun

A system is in neutral equilibrium if its equilibrium is independent of displacements from its original position. A marble S on a flat horizontal surface is an example.

Ibeere 3 Ìròyìn

Three cells each of emf, 1.0 V, and internal resistance, \(2\,\Omega\), are connected in parallel across a \(3\,\Omega\) resistor. Determine the current in the resistor.

0.90A

0.39A

0.30A

0.01A

Awọn alaye Idahun

Given Data: Emf = 1v, r = 2 ohms, R = 3 ohms, I = ?

3 resistance in parallel = $\frac{1}{r_{1}}$ $\frac{1}{r_{2}}$ + $\frac{1}{r_{3}}$

$\frac{1}{r_{T}}$ = $\frac{1}{2}$ + $\frac{1}{2}$ + $\frac{1}{2}$

$\frac{1}{r_{T}}$ = $\frac{1 + 1 + 1}{2}$

$\frac{1}{r_{T}}$ = $\frac{3}{2}$

cross multiply

r $_{T}$ = $\frac{2}{3}$ or 0.67

E = I(R+r)

1 = I(3+0.67)

1 = I(3.67)

1 ÷ 3.67 = I

0.27 = I

: I ≈ 0.30A

Ibeere 4 Ìròyìn

The linear expansivity, \( \alpha \), and cubic expansivity, \( \gamma \), of a material are related by the equation?

γ

=a

γ

=3

α

γ

=2a

γ

=

\frac{1}{3} α

Awọn alaye Idahun

cubic and linear expansivity are related by this equation. γ=3α.

Ka ìwé ẹ̀kọ́ nípa Thermal Expansion (JAMB)

Thermal Expansion

Ibeere 8 Ìròyìn

If the kinetic energy of an electron is 100 eV, what is the wavelength of the de-Broglie wave associated with it? [h = 6.6 x \(10^{-34}\) J s, e = 1.6 x \(10^{19}\) C, \(m_e\), = 9.1 x \(10^{-31}\) kg]

1.22 x 10

^{- 10}

m

4.10 x 10

^{- 10}

m

3.90 x 10

^{- 10}

m

5.50 x 10

^{- 14}

m

Awọn alaye Idahun

de broglie wavelength formula in terms of kinetic energy:

λ = $\frac{h}{\sqrt{2 m E}}$

λ = $\frac{6.6 * 10^{- 34}}{\sqrt{2 * 9.1 * 10^{- 31} * 100}}$

λ = 5.50 x 10 $^{- 14}$ m

Ka ìwé ẹ̀kọ́ nípa Thermal Expansion (JAMB)

Thermal Expansion

Ibeere 10 Ìròyìn

The joule is equivalent to?

Kg m

^{2}

s

^{- 1}

Kg

^{2}

m s

^{- 2}

Kg m

^{2}

s

^{- 2}

Kg m s

^{- 1}

Awọn alaye Idahun

Joule as the unit of work done or energy used.

Force = mass × acceleration
Work = Force × Distance
Work = mass x acceleration x distance

Joule = kg × $\frac{m}{s^{2}}$ × m

→ kg m $^{2}$ s $^{- 2}$

Ka ìwé ẹ̀kọ́ nípa Motion (JAMB)

Ka ìwé ẹ̀kọ́ nípa Measurements And Units (JAMB)

Measurements And Units

Ibeere 14 Ìròyìn

The engine of a car provides a forward force of \(1240\ \mathrm{N}\) and the total resistive force on the car is \(800\mathrm{N}\). If the mass of the car is \(1220\ \mathrm{kg}\), determine the distance the car has to travel from the rest before acquiring a speed of \(4\ \mathrm{m\ s^{-1}}\).

44.0 m

22.2 m

11.1 m

5.5 m

Awọn alaye Idahun

Acceleration[a] = $\frac{[f o r w a r d - r e s i s t i v e] f o r c e}{m a s s}$

a = $\frac{1240 - 800}{1220}$ → $\frac{440 - 800}{1220}$

a = 0.36m/s $^{2}$ , v = 4m/s, s = ?

Second equation of motion:

s is distance
u is initial velocity
v is final velocity
a is acceleration

v $^{2}$ = u $^{2}$ + 2as

4 $^{2}$ = 0 $^{2}$ + 2 * 0.36 * s

16 = 0.72s

22.2m = s

Ibeere 22 Ìròyìn

A galvanometer with a full-scale deflection of 20 mA is Converted to read 8 K by connecting a \(395\,\Omega\) resistor in series with it. Determine the internal resistance of the galvanometer

2.5

Ω

5.0

Ω

8.0

Ω

10.0

Ω

Awọn alaye Idahun

r = resistance of the galvanometer

l = current through galvanometer = 20mA or 0.02A

V1 = p.d across the galvanometer = I X r = 0.02 X r

: V1 = 0.02r

V2 = p.d across the multiplier = 8 - 0.02r

R = resistance of the multiplier = 395Ω

where R = $\frac{V}{I}$

--> 395 = $\frac{8 - 0.02 r}{0.02}$

CROSS MULTIPLY

8−0.02r = 395 * 0.02

8−0.02r = 7.9

--> 0.02r = 8 - 7.9

∴ r = $\frac{0.1}{0.02}$

= 5Ω

Ka ìwé ẹ̀kọ́ nípa Electrostatics (JAMB)

Electrostatics

Ibeere 23 Ìròyìn

An inductor of inductance 10 H is connected across an a.c circuit source of 50 V, 100 Hz. What is the current in the circuit? [\( \pi = 3.14 \)]

0.200A

0.070A

0.050A

0.008A

Awọn alaye Idahun

Given Data: L = 10, V = 50, F = 100, I = ?

Inductive Reactance [X $_{L}$ ] = 2 $π$ FL → 2 * 3.14 * 100 * 10

X $_{L}$ = 6,280

Current[I] = $\frac{V}{X_{L}}$ → $\frac{50}{6280}$

I = 0.0079

≈ 0.008A

Ka ìwé ẹ̀kọ́ nípa Light (JAMB)

Ibeere 30 Ìròyìn

The period of a 10 kHz radio wave traveling at \(10^8\) ms\(^{-1}\) is--

3.0 x 10

^{- 5}

s

1.0 x 10

^{- 4}

s

1.0 x 10

^{4}

s

3.0 x 10

^{4}

s

Awọn alaye Idahun

The formula for the period of a wave is given by T = 1/f, where T is the period and f is the frequency. In this case, the frequency of the radio wave is 10 kHz, which means that f = 10,000 Hz. We can use the formula v = λf, where v is the velocity of the wave, λ is the wavelength, and f is the frequency. Solving for λ, we get λ = v/f. Substituting the given values, we get λ = 10 m/s / 10,000 Hz = 0.001 m. Now, we can use the formula T = λ/v to find the period. Substituting the given values, we get T = 0.001 m / 10 m/s = 0.0001 s. Therefore, the period of the 10 kHz radio wave traveling at 10 m/s is 0.0001 seconds or 1.0 x 10^-4 s. The answer is the second option.

Ka ìwé ẹ̀kọ́ nípa Electromagnetic Waves: Types Of Radiation In Electromagnetic Spectrum (WAEC)

Electromagnetic Waves: Types Of Radiation In Electromagnetic Spectrum

Ibeere 33 Ìròyìn

A lamp is rated 240 V, 60 W. Determine the resistance of the lamp when lit?

120

Ω

240

Ω

540

Ω

960

Ω

Awọn alaye Idahun

P = 60w, V = 240v, R = ?

P = $\frac{V^{2}}{R}$

: 60 = $\frac{240^{2}}{R}$

→ R * 60 = 57,600

R = $\frac{57, 600}{60}$

R = 960 $Ω$

Ka ìwé ẹ̀kọ́ nípa Current Electricity (JAMB)

Current Electricity

Ibeere 47 Ìròyìn

The correct relationship between the displacement, s, of a particle initially at rest in a linear motion and the time, t, is?

s $α$ t $^{- 2}$

s

α

t

^{- 1}

s

α

t

s

α

t

^{2}

Awọn alaye Idahun

The correct relationship between the displacement, s, of a particle initially at rest in a linear motion and the time, t, is s α t2. This means that the displacement of a particle is directly proportional to the square of the time elapsed when the particle is moving in a straight line with a constant acceleration. In other words, if the time is doubled, the displacement will be four times greater; if the time is tripled, the displacement will be nine times greater, and so on. This relationship is also known as the second equation of motion, which is commonly used in physics to describe the motion of objects under constant acceleration.

Ka ìwé ẹ̀kọ́ nípa Rectilinear Acceleration (WAEC)

Ka ìwé ẹ̀kọ́ nípa Speed And Velocity (WAEC)

Rectilinear Acceleration

Speed And Velocity

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