PHY102: Electricity, Magnetism & Modern Physics TMA3

 PHY102: Electricity, Magnetism & Modern Physics TMA3

Instructions: Answer All .
After Submission, you will not be able to answer these questions

Question 1 : ______________________ forces, hold electrons to nuclei, atoms and molecules together to give rise to bulk matter
electrostatic
electrolite
electromotive
electric

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Question 2 : A ______________________ is the amount of charge that flow through a cross-section of a wire in one second if there is a steady current of one ampere (I A) in the wire
coulomb
potential
Hooke's
electric charge

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Question 3 : There are _____________ types of elctric charges
four
three
two
one

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Question 4 : Two ebonite rods rubbed with fur and suspended from a rigid support close to each other by threads will ____________________ each other
relax
contract
attract
repel

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Question 5 : A voltmeter connected across a 60Hz ac source reads 240V. Write down the expression of the instanteneous voltage as a function of time.
240cos339.4t
240sin339.4t
339.4sin377t
377cos339.4t

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Question 6 : The work function of a metal is 3.45eV. Calculate th maximum wavelength of a photon that can eject photelectrons from the metal
$3.6\times {10}^{-7}$

m
$3.4\times {10}^{-7}$m
$2.4\times {10}^{-8}$m
$1.6\times {10}^{-6}$m

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Question 7 : The half-life of a certain radioactive isotope is 32 hours. What fraction of the sample would remain after 16 huors?
0.25
0.71
0.62
0.50

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Question 8 : A potentiometer wire of length 100cm has a resistance of 10$\Omega$. It is connected in series to to a resistance R and a cell of emf 2V and negligible internal resistance. A source of emf of 10mV is balanced by a length of 40cm of the potentiometer wire. What is the value of the resistance R?
2000$\Omega$
950$\Omega$
200$\Omega$
790$\Omega$

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Question 9 : A spectral line is emitted when an atom undergoes transition between two levels with a difference in energy of 2.4eV. What is the wavelength of the line?
287nm
377angstrome units
518nm
507angstrome units

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Question 10 : The law of _____________________ of charge states that the total electric charge in an isolated system, that is, the algebraic sum of the positive and negative charge present at any time, does not change
moment
energy
conservation
momentum

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Question 11 : An RLC circiut contains an ac voltage source with rms value of 50V and has a frequency of 600Hz. Suppose that a resistance R = 20 $\Omega$, capacitance C = 10.0 $\mu$F and an inductance L = 4.0mH are connected in series to the source. Find the current in the circuit and the voltmeter reading across the inductor.
0.13A and 12.1V
4.0A and 23.1V
2.17A and 32.8V
1.6A and 24.2V

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Question 12 : The electric field due to a distribution of charges, according to the _________________________ principle, is the vector sum of the fields of the individual charges making up the distribution
permeability
permittivity
superposition
distributive

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Question 13 : An air-cored transformer is assumed to be 100% efficient. The ratio of the secondary turns to the primary turns is 1:20. A 240V ac supply is connected to the primary coil and a $6\Omega$ load is connected to the secondary coil. what is the current in the primary coil?
40.0A
2.0A
0.14A
0.10A

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Question 14 : When a copper surface is illuminated by radiation of wavelength 2537 angstrome units the value of the stopping potential is found to be 0.24volts. Calculate the work function of copper.
7.46eV
3.26eV
2.67eV
4.48eV

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Question 15 : An RLC circuit is used to tune a radio set to receive NOUN RADIO broadcasting at 105.9MHz in the FM band. The resistance and the inductance of the circuit of the radio set are $12\Omega$ and 1.4$\mu$H respectively. What capacitance should the circuit have?
1.64pF
1.33mF
2.11pF
1.51$\mu$F

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Question 16 : In the relation $k=\frac{1}{4\pi {ϵ}_o}$, ${ϵ}_o$ is the ___________________ of free space
permeability
permittivity
momentum
Coulomb

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Question 17 : The force exerted by charged particles on each other when they are at rest in a frame of reference is called __________________ force
electromotive
electrostatic
electrolite
electric

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Question 18 : An ac circuit consists of a voltage source $v=200sin120\pi t$ and a $6\mu$F capacitor in series. Calculate the current established in the circuit
0.32A
0.64A
2.13A
1.24A

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Question 19 : Objects with net unlike charges ____________________ each other
attract
repel
contract
relax

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Question 20 : If $$Q_1$$ and $$Q_2$$ are the magnitude of two charges and r the distance between them, ________________'s law states that the electric force exerted by one charge on the other F is $$F=k\frac{Q_1{Q}_2}{r^2}$$, where k is a constant
electric charge
Hooke's
potential
Coulomb

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