Description : A typical nucleus is less than _____ in diameter. a) 1010 m b) 10-10 m c) 1014 m d) 10 -14 m
Last Answer : d) 10 -14 m
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 : Semiconductors have electron number density of order A. 1024 m-3 B. 1020 m-3 C. 1012 m-3 D. 1023 m-3
Last Answer : 1023 m-3
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 S.I. unit of Rydberg’s constant is a) m-2 b) m-1 c) cm-1 d) cm-2
Last Answer : b) m-1
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 : Actual velocity of electrons between collisions is A. 1030 m s-1 B. 1020 m s-1 C. 102 m s-1 D. 105 m s-1
Last Answer : 1020 m s-1
Description : The radius of hydrogen atom is about a) 5 x 10-11 m b) 5 x 10-11 cm c) 5 x 10-11 mm d) 5 x 10-11 dm
Last Answer : a) 5 x 10-11 m
Description : An electron is travelling at right angles to a uniform magnetic field of flux density 1.2 mT with a speed of 8 × 106 m s-1, the radius of circular path followed by electron is A. 3.8 cm B. 3.7 cm C. 3.6 cm D. 3.5 cm
Last Answer : 3.8 cm
Description : The minimum charge on any electron be less than: (a) 1.6×10−19C (b) 3.2×10−19C (c) 1.8×10−19C (d) 9.1×10−19C
Last Answer : (a) 1.6×10−19C
Description : Consider a source computer(S) transmitting a file of size 106 bits to a destination computer (D)over a network of two routers (R1 and R2) and three links(L1, L2, and L3). L1connects S to R1; L2 connects R1 to ... file from S to D? a. 1005 ms b. 1010 ms c. 3000 ms d. 3003 ms Answer: Option(a)
Last Answer : a. 1005 ms
Description : An α particle moves perpendicular to a constant magnetic field of strength 1.2 T in a circular path of radius 0.7 m. The speed of α particle in ms-1 is ______________ a) 2.7 × 107 b) 2.6 × 107 c) 3.2 × 107 d) 2.0 × 107
Last Answer : a) 2.7 × 107
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 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 : 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 : 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 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 : The electron was discovered by a) Burcherer b) Anderson c) Chadwick d) J. J Thomson
Last Answer : d) J. J Thomson
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 : 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 : Number density for copper isA. 10-29 m-3 B. 1030 m-3 C. 1029 m-3 D. 1020 m-3
Last Answer : 1029 m-3
Description : A couple applied to a flywheel of mass 5 kg and of radius of gyration 20 cm produces an angular acceleration of 4 radians/sec2. The torque applied in dyne cm is a.8 x 104 b.8 x 106 c.8 x 107 d.8 x 108 e.8 x 1010
Last Answer : b. 8 x 106
Description : Terminal potential difference of a battery is greater than its emf when a. the internal resistance of battery is infinite b. the internal resistance of battery is zero c. the battery is charged d. the battery is discharged
Last Answer : c. the battery is charged
Description : S.I unit of strain is a) Newton b) N m–2 c) Pascal d) no unit
Last Answer : a) Newton
Description : S.I unit of stress is: a) N/m b) N m c) Nm–2 d) Newton
Last Answer : c) Nm–2
Description : In a thyristor Latching current is ________ than Holding current a) Equal b) Less c) Greater d) None
Last Answer : Ans: Greater
Description : In p-n-p transistor, collector current is (a) Equal to emitter current (b) slightly less than emitter current (c) greater than emitter current (d) any of above
Last Answer : (c) greater than emitter current
Last Answer : The efficiency of transformer is Greater than electrical Machine because there is no rotational losses in transformer and there is no air gap losses in transformer so losses is less in transformer compare to electrical machine so efficiency is higher in case of transformer.
Description : Please ripley me due to emergency
Last Answer : To calculate the flux density in the ring, you need to use the following formula: B = (μ * I * N) / (2 * π * r) where: B is the flux density in the ring (in teslas) μ is the relative permeability ... 2 * π * 0.127 m) = 0.53 T So the flux density in the ring would be approximately 0.53 teslas.
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 : The value of first quantized Bohr orbit radius of hydrogen atom is a) 0.0053 nm b) 5.3 nm c) 0.053 nm d) 0.053 cm
Last Answer : c) 0.053 nm
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 : In human flesh, the three light elements which predominate, and allow greater amount of incident X-rays to pass through them are a) oxygen, nitrogen , hydrogen b) oxygen, hydrogen, helium c) oxygen, hydrogen, carbon d) carbon, nitrogen, oxygen
Last Answer : c) oxygen, hydrogen, carbon
Description : Dry land farming in India is largely confined to areas with rainfall less than - a. 100 cm b. 85 cm c. 80 cm d. 75 cm
Last Answer : d. 75 cm
Description : how,he speed of sound is about 3.4 × 102 meters per second. Mark is performing a science experiment and he needs to know how far sound travels in 3 × 1010 seconds. If Mark uses a calculator to solve this problem, how will the calculator show the answer?
Last Answer : 10200000000000
Description : The entire range of the electromagnetic spectrum spans a large spectrum of wave lengths varying from: (A) 10-10 to 106 m (B) 10-8 to 106 m (C) 10-10 to 1010 m (D) 10-8 to 108 m
Last Answer : Answer: Option A
Description : In hydrogen atom, the electron is making `6.6xx10^(15) rev//sec` around the nucleus in an orbit of radius `0.528 A`. The magnetic moment `(A-m^(2)) wi
Last Answer : In hydrogen atom, the electron is making `6.6xx10^(15) rev//sec` around the nucleus in an orbit of radius `0. ... ` C. `1xx10^(-23)` D. `1xx10^(-27)`
Description : If a material object moves with the speed of light ‘c’ its mass becomes a) equal to its rest mass b) Four times of its rest mass c) Double of its rest mass d) Infinite
Last Answer : d) Infinite
Description : A magnetic field acts on a charged particles so as to change its: a. speed b. energy c. direction of motion d. all of these
Last Answer : Only direction of motion will change ...it means velocity will change but speed same
Description : Thehigherthe index number a. the higher the speed of light b. the lower the speed of light c. has no effect on the speed of light d. the shorter the wavelength propagation
Last Answer : a. the higher the speed of light
Description : How is the speed of a DC motor varied?
Last Answer : To vary the speed of a DC motor we need a constant voltage power supply with a series POT resistor of higher watt rating. A Pulse Width Modulator (PWM) can be used.
Description : How is the speed of a 3-phase induction motor varied?
Last Answer : The speed of a normal 3-phase induction motor is a function of the frequency of the supply voltage. Changing the speed of such a motor hence requires building a 3-phase power frequency ... realised by using power MOSFETs (or IGBTs) capable of handling high voltages and fast switching speeds.
Description : In annihilation of matter the photons produced fly off at the speed of a) Light b) Sound c) Twice the speed of light d) None
Last Answer : a) Light
Description : A rod at rest appears to an observer just a mere point when he moves across it as speed, a) Equal to the speed of light b) Double the speed of light c) Three-fourth the speed of light d) None of the above
Last Answer : a) Equal to the speed of light
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 : Which of the following quantities change when a proton moves at right angles to a magnetic field? a) Momentum b) Energy c) Speed d) All of these
Last Answer : a) Momentum