Category: PHY102 0 PHY102 1 / 50  From Gauss’ law which of the following is NOT correct? 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 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 outward flux of electric field through an enclosed surface is proportional to the electric charges enclosed The total electric flux through a cylinder placed in an electric field with its axis parallel to the field is zero 2 / 50 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 $12Omega$ and 1.4$mu$H respectively. What capacitance should the circuit have? 2.11pF 1.64pF 1.51$\mu$F 1.33mF 3 / 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. Check 4 / 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? 518nm 507angstrome units 287nm 377angstrome units 5 / 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. 14.43V 9.17V 17.49V 6.17V 6 / 50 The force that is responsible for holding electrons to nuclei to form atoms is called the --------------------------- force Check 7 / 50 The magnitude of the forces between charged spheres was first investigated by Charles --------------------------- Check 8 / 50 The surface integral of the electric field E over a surface is defined to be electric --------------------------- Check 9 / 50 The magnitude and direction of the earth's field varies with position over the --------------------------- surface. Check 10 / 50 The --------------------------- is the SI Unit of electric charge Check 11 / 50  In the circuit shown, each of the cells has an emf of 2V and internal resistance of $0.1Omega$. Find the current in through the $0.5Omega$ 2.44A 0.13A 1.27A 3.45A 12 / 50 The resistivity of a semiconductor decreases rapidly with increasing ---------------------------. Check 13 / 50  Which of the following can be used to charge a metal rod that si held in your hand? Rub it with ______ fur wool It cannot be done silk 14 / 50 When a dielectric material is inserted between the plates of a capacitor it increases its --------------------------- Check 15 / 50 Kirchhof's junction rule is statement of conservation of ----------- mass charge energy momentum 16 / 50 When a charge density depends only on the perpendicular distance from a plane, the charge distribution is said to have--------------------------- symmetry. Check 17 / 50 According to Faraday's law, the magnitude of the induced e.m.f is proportional to the rate of change of --------------------------- linking the circuit. Check 18 / 50  Which of the following is a conductor silk glass plastic copper 19 / 50  What are the dimensions of the constant k in Coulomb’s law of electrostatics? $ML^{2}T^{3}A^{-2}$ $ ML^{3}T^{-4}A^{-2}$ $M^{-2}L^{3}T^{2}A^{-1}$ $ML^{2}T{-4} T{-2}A{-1}$ 20 / 50  An electron enters a uniform magnetic field 0.20 T at an angle of $30^{o}$ the field. Determine the pitch of the helical path assuming its speed is $3times10^{7}$ m/s 46.5 m 37.8 m 56.1 m 90.6 m 21 / 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 zero electric field is toward P, electric potential is positive electric field is toward Q, electric potential is negative electric field is toward Q, electric potential is zero 22 / 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? $6.0\times10^{4}$m/s $7.0\times10^{4}$m/s $5.0\times10^{4}$m/s $8.0\times10^{4}$m/s 23 / 50  A magnetic field does not exert a force on a _________ stationary charge steel pin magnet moving charge 24 / 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 terminal potential difference energy per coulomb dissipated in the external (load) resistance 25 / 50 For how long must a steady current of 2A flow through a copper voltameter to deposit $10^{-3}$kg of copper? Z for coper is 0.000329g/C 30.2min 25.3min 42.1min 22.6min 26 / 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? $3\times10^{3}$ m/s $4\times10^{7}$ m/s $2\times10^{5}$ m/s $5\times10^{4}$ m/s 27 / 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 $3.4\times10^{-7}$m $2.4\times10^{-8}$m $3.6\times10^{-7}$m $1.6\times10^{-6}$m 28 / 50 A charge distribution in which the charge density at any point depends only on the distance of the point from a central point and not on the direction is said to be spherically --------------------------- Check 29 / 50 Gauss's law applies to any hypothetical closed surface called --------------------------- surface. Check 30 / 50 For capacitors in parallel, the potential difference across each capacitor is --------------------------- Check 31 / 50 A positively charged object repels positively charged object neutral objects negatively charged objects both positively and negatively charged objects 32 / 50 In the method of charging by friction, The algebraic sum of the individual charges that is the net charge is ---------------------------. Check 33 / 50 Field lines are drawn such that the lines per unit cross-section area is proportional to ---------------------------field. Check 34 / 50 Gaussian surface is an imaginary closed --------------------------- Check 35 / 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? 0.10A 40.0A 0.14A 2.0A 36 / 50 The magnetic North is found by suspending a bar magnet freely on the --------------------------- axis. Check 37 / 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} ${-}4.1\times10^{-3}$C $4.2\times10^-{6}$ C $3.2\times10^{-6}$ C ${-}3.1\times10^{-6}C 38 / 50  A potentiometer wire of length 100cm has a resistance of 10$Omega$. It is connected in series to to a resistance R and a cell of emf 2V and negligible internal resistance. A source of emf of 10mV is balanced by a length of 40cm of the potentiometer wire. What is the value of the resistance R? 200$\Omega$ 950$\Omega$ 2000$\Omega$ 790$\Omega$ 39 / 50 The force between electric charges is known as --------------------------- Check 40 / 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 41 / 50 The --------------------------- number is the total number of neutrons and protons. Check 42 / 50 The direction of the electric field is opposite to that of the force if the charge is --------------------------- Check 43 / 50 An alpha particle is a --------------------------- nucleus consisting of 2 protons and 2 neutrons. Check 44 / 50 The following are true about electric field lines except that they ______ give the direction of motion of a unit positive test-charge under the action of the electrostatic force do not intersect one another are discontinuous and may terminate in a vacuum are drawn such that the magnitude of the field is proportional to the number of lines crossing a unit area perpendicular to the lines 45 / 50 At the _______ a dipping compass needle is horizontal and at the magnetic poles it is vertical. Check 46 / 50  Find the current in through the $0.3Omega$ in the circuit shown 1.33A 3.27A 2.15A 0.69A 47 / 50  1 volt is equal to ________ 1 J/s C 1 N/C 1 J/C 1 watt/C 48 / 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. 2.17A and 32.8V 4.0A and 23.1V 0.13A and 12.1V 1.6A and 24.2V 49 / 50 The work done in taking a unit positive charge from one point to another in electric field is --------------------------- of the path chosen between the two points. Check 50 / 50 In the cathode ray oscilloscope, when fast moving electrons strike the glass screen coated with zinc and sulphide they cause ---------------------------. Check Restart quiz Rate this quiz Send feedback
