PHY102

Category: PHY102

PHY102

1 / 50

Gaussian surface is an imaginary closed ---------------------------

2 / 50

For capacitors in parallel, the potential difference across each capacitor is ---------------------------

3 / 50

A galvanometer of resistance $120Omega$ a full scale deflection with a current of 0.0005A. How would you convert it to an ammeter that reads a maximum current of 5A?

connect $200.12\Omega$ in series to it

connect $0.012\Omega$ in parallel to it

connect $2000\Omega$ in parallel to it

connect $20.10\Omega$ in series to it

4 / 50

The electric potential difference between two points A and B is 42 V. What is the work done by an external agent in carrying a charge of 5.0$times 10^{-5}$ C from A to B at constant speed?

$2.1\times10^{-3}$ J

$8.4\times10^{-3}$ J

$8.4\times10^{-4}$ J

21$\times10-4$J

5 / 50

A magnetic field does not exert a force on a _________

steel pin

stationary charge

moving charge

magnet

6 / 50

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 $6Omega$ load is connected to the secondary coil. what is the current in the primary coil?

0.14A

40.0A

0.10A

2.0A

7 / 50

A series circuit consisting of an uncharged $42mu$F capacitor and $10 MOmegaega$ resistor is connected to 100V power source. What are the current in the circuit and the charge on the capacitor after one time constant?

$1.3\mu$A and $52\mu$C

$3.7\mu$A and $126\mu$C

$7.2\mu$A and $100\mu$C

$4.6\mu$A andC 221\mu$C

8 / 50

As charge increases, electric flux density ---------------------------

9 / 50

<p style="text-align:left">Six equal point charges Q = 10nC are located at 2,3, 4,5,6,7m. Find the potential at origin.

10 / 50

For capacitors connected in series each has the same ____________.

11 / 50

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

518nm

507angstrome units

377angstrome units

12 / 50

What is the self - inductance of an air-core solenoid, 1m long and 0.05m in diameter, if it has 1400 turns?

2.42mH

3.63mH

4.84mH

5.23mH

13 / 50

The magnetic flux through each loop of a 35-loop coil is given by $(3.6t-0.71t^{3})times10^{-2}Tm^{2}$, where the time is in seconds. Determine the induced emf at t=5.0s.

9.17V

6.17V

14.43V

17.49V

14 / 50

Kirchhof's junction rule is statement of conservation of -----------

energy

mass

momentum

charge

15 / 50

A rectangular coil of dimensions 20 cm by 15 cm lies with its plane parallel to a magnetic field of $ 0.5 W/$m^{2}$. The coil, carrying a current of 10 A experiences a torque of 4.5 Nm in the field. How many loops has the coil?

100

16 / 50

A positive ion passes through an electric and magnetic fields which are mutually perpendicular. The electric field strength is 20.0kV/m while the magnetic flux density is 0.40T. At what speed will the ion pass through undeflected?

$8.0\times10^{4}$m/s

$6.0\times10^{4}$m/s

$5.0\times10^{4}$m/s

$7.0\times10^{4}$m/s

17 / 50

Kirchhof's loop rule is statement of conservation of __________

mass

momentum

energy

charge

18 / 50

Electric charge between two bodies can be produced by ---------------------------

19 / 50

A body that absorbs all radiations falling on it is known as ---------------------------.

20 / 50

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.

1.6A and 24.2V

2.17A and 32.8V

0.13A and 12.1V

4.0A and 23.1V

21 / 50

If the steady current in a wire is coming directly toward you, the magnetic field lines

circle the wire in the clockwise direction

point radially inward

circle the wire in the counterclockwise direction

point radially outward

22 / 50

Find the force on a charge 2C in a field 1Vm<sup>-1</sup>---------------------------

23 / 50

A conductor 2cm long carrying a current of 8A lies at right angles to a magnetic field of which the flux density is 1.0T. Calculate the force exerted on the conductor

0.20N

0.45N

0.25N

0.16N

24 / 50

The resistivity of a semiconductor decreases rapidly with increasing ---------------------------.

25 / 50

Neutral objects constitute of equal ---------------------------

26 / 50

The --------------------------- number is the total number of neutrons and protons.

27 / 50

The principle that electric forces add vectorially is known as the principle of ---------------------------

28 / 50

The term 'lost volts' refers to -----------

energy per coulomb wasted to heat up the connecting wires

energy per coulomb dissipated in the internal resistance of the source of emf

energy per coulomb dissipated in the external (load) resistance

terminal potential difference

29 / 50

The work function of a metal is 3.45eV. Calculate th maximum wavelength of a photon that can eject photo-electrons from the metal

$1.6\times10^{-6}$m

$2.4\times10^{-8}$m

$3.4\times10^{-7}$m

$3.6\times10^{-7}$m

30 / 50

In the space surrounding a wire carrying a steady current, there exists ________

an oscillating magnetic field

no magnetic field

a magnetic field circling the wire

a magnetic field pointing radially outward

31 / 50

An electric field of 50 kV/m is perpendicular to a magnetic field 0.25 T. What is the velocity of a charge whose initial of motion is perpendicular to both fields and which passes through the fields undeflected?

$5\times10^{4}$ m/s

$2\times10^{5}$ m/s

$4\times10^{7}$ m/s

$3\times10^{3}$ m/s

32 / 50

The surface integral of the electric field E over a surface is defined to be electric ---------------------------

33 / 50

Two charges $Q_{1} = 500mu{C}$ and $Q_{2} = 100mu{C}$ are located on the XY plane at the positions $r_{1} = 3vec{j} m and r_{2} = 4vec{i}$ m. Find the force exerted on the $Q_{2}$

$10.8\vec{i} – 14.4\vec{j}$ N

$10.8\vec{i} + 14.4\vec{j}$ N

$14.4\vec{i} – 10.8\vec{j}$ N

$14.4\vec{i} + 10.8\vec{j}$ N

34 / 50

The minimum energy required to liberate an electron from a metal surface is called ---------------------------.

35 / 50

Charges of ${+}2$ C and ${-2}$ C are situated at points P and Q respectively which are at a distance apart. A point X is mid-way between P and Q. Which of the following correctly describes the electric field and the electric potential at point X?

electric field is toward P, electric potential is positive

electric field is toward P, electric potential zero

electric field is toward Q, electric potential is negative

electric field is toward Q, electric potential is zero

36 / 50

Two identical balls balls P and Q, each of mass 0.20 g, carry identical charges and are suspended by two threads of equal length. The balls position themselves at equilibrium such that the angle between the threads is 60_{o}.If the distance between the the balls is 0.5m, find the charge on each of them. Take g = 9.8 m/s^{2}

$3.1\times10^{-5}$ C

$1.8\times10^-{7}C

$1.1\times10^{-3}$C

$2.3\times10^-{6}$C

37 / 50

The force that is responsible for holding electrons to nuclei to form atoms is called the --------------------------- force

38 / 50

From Gauss’ law which of the following is NOT correct?

The outward flux of electric field through an enclosed surface is proportional to the electric charges enclosed

The electric flux through a Gaussian surface is a vector product of the electric field and a unit vector perpendicular to and outward from the surface

The field at a point outside a spherically symmetric charge is the same as the electric field at the same point due to a point charge at its centre.

The total electric flux through a cylinder placed in an electric field with its axis parallel to the field is zero

39 / 50

A negative charge ---------------------------negative charge

40 / 50

The --------------------------- is the SI Unit of electric charge

41 / 50

When a dielectric material is inserted between the plates of a capacitor it increases its ---------------------------

42 / 50

The electric flux is a --------------------------- quantity.

43 / 50

A tiny ball of mass 0.60 g is suspended from a rigid support with a piece of thread in a horizontal electric field of intensity 700 N/C. The ball is in equilibrium when the thread is inclined at an angle of 20_{o} to the vertical. What are the magnitude and sign of the charge on the ball? Take g = 9.8m/s^{2}

${-}3.1\times10^{-6}C

$4.2\times10^-{6}$ C

$3.2\times10^{-6}$ C

${-}4.1\times10^{-3}$C

44 / 50

Electric flux density is a function of ---------------------------

45 / 50

Whose law is employed in electrostatics ?

46 / 50

Field lines are drawn such that the lines per unit cross-section area is proportional to ---------------------------field.

47 / 50

The energy stored in a system of charges is known as electrostatic potential ---------------------------

48 / 50

In the method of charging by friction, The algebraic sum of the individual charges that is the net charge is ---------------------------.

49 / 50

Three point charges $$2mu{C$}, ${-}4mu{C}$$, and $$6mu{C}$$ are held at the corners of an equilateral triangle with sides equal to 3 cm.What is the resultant force in newtons on the $$2mu{C}$$ charge?

$40\vec{i}-63.7\vec{j}$

${-}80\vec{i}+69.3\vec{j}$

${-}40\vec{i}+63.7\vec{j}$

$80\vec{i}-69.3\vec{j}$

50 / 50

A huge spark due to electric discharge in the atmosphere produces all of the following except ______

Lightning

gamma radiation.

Rapid expansion of surrounding air

shock waves

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