Practise questions | Salam Academy

SA-9702-EC1-0032 marksL2 StandardCalculatorDrift velocity

A copper wire of cross-sectional area

1.0\times10^{-6}

m² carries a current of

2.0

A. Copper has

8.5\times10^{28}

free electrons per m³. Calculate the drift velocity, in mm s⁻¹.

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SA-9702-EC1-0051 markL2 StandardCalculatorCharge & current

Which charge is not possible on an oil drop?

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SA-9702-EC2-0042 marksL2 StandardCalculatorElectrical power

A heater is rated

1000

W on a

230

V supply. Calculate its resistance.

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SA-9702-EC3-0022 marksL2 StandardCalculatorResistivity

A wire

0.50

m long with cross-sectional area

1.0\times10^{-7}

m² has resistance

4.0

Ω. Calculate its resistivity, in units of

10^{-7}

Ω m.

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SA-9702-EC3-0032 marksL2 StandardCalculatorResistivity

Copper has resistivity

1.7\times10^{-8}

Ω m. Calculate the length of copper wire of cross-sectional area

1.0\times10^{-6}

m² that has a resistance of

10

Ω.

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SA-9702-EF1-0032 marksL2 StandardCalculatorUniform fields

Calculate the acceleration of an electron in a field of

2.5\times10^4

V m⁻¹, in units of

10^{15}

m s⁻². (

m_e=9.11\times10^{-31}

kg)

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SA-9702-EF2-0012 marksL2 StandardCalculatorCoulomb's law

Calculate the electric force between a proton and an electron

5.3\times10^{-11}

m apart, in units of

10^{-8}

N. (

\tfrac1{4\pi\varepsilon_0}=8.99\times10^9

N m² C⁻²)

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SA-9702-EF2-0052 marksL2 StandardCalculatorPoint charge field

Charges of

+4.0

μC and

+1.0

μC are

6.0

cm apart. Calculate the distance from the

4.0

μC charge to the neutral point between them, in cm.

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SA-9702-EF3-0022 marksL2 StandardCalculatorElectric potential

An α-particle (charge

+2e

) has kinetic energy

8.0\times10^{-13}

J and travels head-on towards a gold nucleus (charge

+79e

). Calculate the distance of closest approach, in units of

10^{-14}

m. (

\tfrac1{4\pi\varepsilon_0}=8.99\times10^9

N m² C⁻²;

e=1.60\times10^{-19}

C)

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SA-9702-EF3-0051 markL2 StandardCalculatorElectric potential

A

+3.0

μC charge is moved from a point at

50

V to a point at

250

V. Calculate the work done on it, in mJ.

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SA-9702-FD1-0032 marksL2 StandardCalculatorMoments & couples

A uniform beam

2.0

m long and of weight

100

N is hinged at one end. It is held horizontal by a vertical force at the other end. Calculate this force.

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SA-9702-FD1-0042 marksL2 StandardCalculatorMoments & couples

A

40

N force acts on a bar

0.50

m from the pivot, at

30^\circ

to the bar. Calculate its moment about the pivot.

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SA-9702-FD2-0052 marksL2 StandardCalculatorUpthrust

The object in the previous question has a mass of

5.0

kg. Calculate its apparent weight when fully submerged.

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SA-9702-GF1-0012 marksL2 StandardCalculatorLaw of gravitation

Earth (mass

6.0\times10^{24}

kg) and the Moon (mass

7.3\times10^{22}

kg) are

3.8\times10^8

m apart. Calculate the gravitational force between them, in units of

10^{20}

N. (

G=6.67\times10^{-11}

N m² kg⁻²)

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SA-9702-GF1-0022 marksL2 StandardCalculatorField strength

Calculate the gravitational field strength at a height of

400

km above Earth's surface. (Earth: mass

6.0\times10^{24}

kg, radius

6.4\times10^6

m;

G=6.67\times10^{-11}

N m² kg⁻²)

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SA-9702-GF2-0012 marksL2 StandardCalculatorGravitational potential

Calculate the gravitational potential at Earth's surface, in units of

10^7

J kg⁻¹. (Earth: mass

6.0\times10^{24}

kg, radius

6.4\times10^6

m;

G=6.67\times10^{-11}

N m² kg⁻²)

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SA-9702-GF2-0022 marksL2 StandardCalculatorOrbits

Calculate the speed of a satellite in a circular orbit of radius

7.0\times10^6

m around Earth. (

GM=4.0\times10^{14}

N m² kg⁻¹)

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SA-9702-GF2-0041 markL2 StandardCalculatorGravitational potential

Gravitational potential is negative because

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SA-9702-IG1-0012 marksL2 StandardCalculatorIdeal gas equation

A room of volume

50

m³ contains air at

1.0\times10^5

Pa and

20

°C. Calculate the number of moles of air. (

R=8.31

J mol⁻¹ K⁻¹)

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SA-9702-IG1-0052 marksL2 StandardCalculatorThe mole

Calculate the number of moles in

88

g of carbon dioxide (molar mass

44

g mol⁻¹), and hence the number of molecules, in units of

10^{24}

.

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