Description : The minimum energy required to eject an electron from a metal surface is called a) Intensity b) Threshold frequency c) Work function d) Photo energy
Last Answer : c) Work function
Description : Electron can exist in the atom but outside the nucleus because a) speed of electron is equal to the speed of light b) speed of electron is more than speed of light c) speed of electron is less than speed of light d) None of these
Last Answer : c) speed of electron is less than speed of light
Description : The electric intensity at a distance of 1m from the point charge is 1μC is: (a) 9 × 109 N/C (b) 9 × 106 N/C (c) 9 × 103 N/C (d) 9 N/C
Last Answer : c) 9 × 103 N/C
Description : A charge of 10μC and 14.4 μC are 12 cm apart, the force between them is: (a) 9 × 105 N (b) 9 × 107 N (c) 90 N (d) 108 × 107 N
Last Answer : (c) 90 N
Description : An electron moves with a velocity of 2 × 106 ms-1 in the direction of a uniform magnetic field of 0.8 Tesla. The force on electron is a) 8 N b) 2 N c) 4 N d) Zero
Last Answer : d) Zero
Description : The amount of energy required to completely remove an electron from the first Bohr orbit is a) 13.6 MeV b) 13.6 eV c) 1.36 MeV d) 1.36 eV
Last Answer : b) 13.6 eV
Description : In the phenomenon of Laser production, atom can reside in the excited state only for a) 10-6 s b) 10-7 s c) 10-8 s d) 10-9 s
Last Answer : c) 10-8 s
Description : A proton having mass m and charge q is projected into a region having a perpendicular magnetic field. The angle of deviation of proton when it comes out of the region with mv √2 qB ⁄ is a) π/3 b) π/4 c) π/6 d) 2 π/3
Last Answer : b) π/4
Description : The number of electrons in one coulomb charge is equal to: (a) 6.2 × 1018 electrons (b) Zero electrons (c) 1.6 × 10−22 electrons (d) 6.2 × 1021 electrons
Last Answer : (a) 6.2 × 1018 electrons
Description : If electron has to be confined in the nucleus, its speed would have to be greater than a) 1010 cm/s b) 1010 m/s c) 1020 m/s d) 1020 cm/s
Last Answer : b) 1010 m/s
Description : If energy of incident photon is greater than the rest mass energy of electron positron pair, the surplus energy is shared by the pair as, a) Potential energy b) Thermal energy c) Electronic energy d) Kinetic energy
Last Answer : d) Kinetic energy
Description : The total energy of electron in the Bohr orbit is given by the formula, E = a) - ke2 /2r b) - ke2 /2r2 c) - k 2 e/2r d) - ke2 /r
Last Answer : a) - ke2 /2r
Description : The energy required to completely remove an electron from the first Bohr orbit is called a) excited energy b) ionization energy c) accelerated energy d) orbital energy
Last Answer : b) ionization energy
Description : The quantized Bohr orbit radius of electron in hydrogen atom is given by a) n2 r3 b) nr1 c) n2 r2 d) n2 r1
Last Answer : d) n2 r1
Description : The speed of hydrogen electron in the nth orbit is given by vn = a) 2λke2 / nh b) 2πke2 / λh c) 2πke2 / nh d) 2πke2 / h
Last Answer : c) 2πke2
Description : A three dimensional image is obtained by a)Electron microscope b) Scanning electron microscope c) Magnetic imaging d)None of these
Last Answer : b) Scanning electron microscope
Description : The electron was discovered by a) Burcherer b) Anderson c) Chadwick d) J. J Thomson
Last Answer : d) J. J Thomson
Description : A circuit which develops voltage across the horizontal deflection plates is known as a) Time base generator b) Electron gun c) Thermionic diode d) Zener diode
Last Answer : a) Time base generator
Description : ___________ is not affected by a magnetic field a) Change in magnetic flux b) a moving electron c) a stationary proton d) current flowing in a conductor
Last Answer : c) a stationary proton
Description : Two electron beams move parallel to each other. The nature of force between them is a) Attractive b) Repulsive c) Dependent on magnitude of velocity d) None
Last Answer : b) Repulsive
Description : An electron and a neutron enter a magnetic field with the same velocity. Ratio of electron to neutron’s acceleration is a) mn me b) √ mn me c) √ me mn d) me
Last Answer : a) mn me
Description : Red Laser light has a wavelength of a) 630.8 nm b) 630 cm c) 632.8 nm d) 639.9 nm
Last Answer : c) 632.8 nm
Description : Which one of the following quantities is conserved in pair production? a) Energy b) Charge c) Linear momentum d) All
Last Answer : d) All
Description : Which one of the following physical quantities is independent of relativistic speed? a) Mass b) Length c) Time d) Charge
Last Answer : d) Charge
Description : The emitter of a transistor is doped the heaviest because it: (a) Acts as a supplier of charge carriers (b) Dissipates maximum power c) has a large resistance (d) has a small resistance
Last Answer : (a) Acts as a supplier of charge carriers
Description : Depletion region carries _________ (a) +ve charge (b) –ve charge (c) no charge (d) all of above
Last Answer : (c) no charge
Description : N-type region has majority charge carriers as (a) Holes (b) protons (c) neutrons (d) electrons
Last Answer : (d) electrons
Description : Energy stored per unit volume inside the solenoid is called: a. Energy density b. Charge Density c. Mass density d. Volume charge density
Last Answer : energy density is correct
Description : An ideal transformer always obeys the law of conservation of........: a. energy b. momentum c. charge d. Flux
Last Answer : b. momentum
Description : Lenz’s law is in accordance with the law of conservation of: a. momentum b. Angular momentum c. charge d. energy
Last Answer : a. momentum
Description : The fractional change in resistance per kelvin is known as, a. temperature coefficient of resistance b. coefficient of Voltage of charge c. thermal expansion d. all of above
Last Answer : a. temperature coefficient of resistance
Description : When the potential difference of 4 volt is applied across resistance, 10J energy is converted. Find the charge flows. a. 0.20 C b. 2.5C c. 5C d. 10C
Last Answer : b. 2.5C
Description : Kirchhoff 1st law is is manifestation of a. law of conservation of mass b. law of conservation of charge c. law of conservation of energy d. none
Last Answer : b. law of conservation of charge
Description : If 1 ampere current flows through 2m long conductor the charge flow through it in 1 hour will be a. 3600C b. 7200C c. 1C d. 2C
Last Answer : a. 3600C
Description : A charge of 2 coulomb is in a field of intensity 2 N/C. The force on charge is: (a) 4 π N (b) 4 N (c) 0 N (d) 1 N
Last Answer : b) 4 N
Description : The electric field exist around: (a) Charges (b) On the left side (c) At the –ve charge (d) At the +ve charge
Last Answer : (a) Charges
Description : The force per unit charge is called: (a) Electric field (b) Electric field intensity (c) Electric potential energy (d) Electric potential
Last Answer : b) Electric field intensity
Description : The space around the charge within which other charges are influenced by it is called: (a) Electric field (b) Magnetic field (c) Electric flux (d) Electric intensity
Last Answer : a) Electric field
Description : An inkjet printer uses in its operation: (a) Positrons (b) Neutrons (c) An electric charge (d) Photons
Last Answer : (c) An electric charge
Description : The SI unit of charge is: (a) Meter (b) Ampere (c) Coulomb (d) Volt
Last Answer : (c) Coulomb
Description : When current of one ampere is flowing across any cross-section of wire in one second, then the quantity of charge is said to be: (a) One coulomb (b) Three coulomb (c) One micro-coulomb (d) None of above
Last Answer : (a) One coulomb
Description : If the distance between the two charge bodies is halved, the force between them becomes: (a) Half (b) Four time (c) One fourth (d) Doubled
Last Answer : (c) One fourth
Description : A substance contains: (a) Only positive charge (b) Only negative charge (c) Both +ve and −ve charge (d) None of above
Last Answer : (c) Both +ve and −ve charge
Description : The SI unit of charge is: (a) Coulomb (b) Calorie (c) Ampere (d) Joule
Last Answer : a) Coulomb
Description : Themechanicalsplice isbestsuited for a. quicker installation under ideal conditions b. minimum attenuation losses c. field service conditions d. situations in which cost of equipment is not a factor
Last Answer : c. field service conditions
Description : The minimum frequency required to eject electrons from a metallic surface is called a) Critical frequency b) Peak value of frequency c) Threshold frequency d)Photo frequency
Last Answer : c) Threshold frequency
Description : In the plane of AC generator coil is parallel to the field, then emf induced in coil is: a. maximum b. minimum c. zero d. intermediate
Last Answer : b. minimum
Description : In the plane of the A.C generator coil is perpendicular to the field, then induced emf in the coil is: a. Maximum b. minimum c. zero d. intermediate value
Description : When a motor is just started, back emf is almost ______: a. Infinite b. zero c. minimum d. maximum
Last Answer : d. maximum
Description : The magnetic flux φB through a plane element of area A⃗ in a uniform magnetic field B⃗⃗ is minimum at a) θ = 900 b) θ = 00 c) θ = 1800 d) None of these
Last Answer : a) θ = 900