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
Description : When the field is strong, the lines of force are: (a) Closer (b) Parallel (c) Farther (d) All of above 45. The electric lines of force determine the strength of an: (a) Gravitational field (b) Constant field (c) Magnetic field (d) Electric field
Last Answer : d) Electric field
Description : In motor a permanent magnet provides: a. Electric field b. electric flux c. magnetic field d. gravitational field
Last Answer : d. gravitational field
Description : Find the Lorentz force due to a conductor of length 2m carrying a current of 1.5A and magnetic flux density of 12 units. a) 24 b) 36 c) 32 d) 45
Last Answer : c) 32
Description : Find the Lorentz force of a charge 2.5C having an electric field of 5 units and magnetic field of 7.25 units with a velocity 1.5m/s. a) 39.68 b) 68.39 c) 86.93 d) 93.68
Last Answer : a) 39.68
Description : Michael Faraday was known by his work on: (a) Electric force (b) Weak nuclear force (c) Strong nuclear force (d) Gravitational force
Last Answer : (a) Electric force
Description : Which one of the following scientists regarded light as electromagnetic waves? a) Newton b) Galileo c) de Broglie d) Maxwell
Last Answer : d) Maxwell
Description : The magnetic field is _________ inside a solenoid a) Zero b) uniform c) non-uniform d) infinite
Last Answer : b) uniform
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 : A conductor of length L has current I passing through it, when it is placed parallel to a magnetic field. The force experienced by the conductor will be (a) zero (b) BLI (c) B2LI (d) BLI2
Last Answer : (a) zero
Description : The left hand rule correlates to (a) current, induced e.m.f. and direction of force on a conductor (b) magnetic field, electric field and direction of force on a conductor (c) self induction, ... and direction of force on a conductor (d) current, magnetic field and direction of force on a conductor
Last Answer : (d) current, magnetic field and direction of force on a conductor
Description : Fleming's left hand rule is used to find (a) direction of magnetic field due to current carrying conductor (b) direction of flux in a solenoid (c) direction of force on a current carrying conductor in a magnetic field (d) polarity of a magnetic pole
Last Answer : (c) direction of force on a current carrying conductor in a magnetic field
Description : When an iron piece is placed in a magnetic field (a) the magnetic lines of force will bend away from their usual paths in order to go away from the piece (b) the magnetic lines of force will bend ... to pass through the piece (c) the magnetic field will not be affected (d) the iron piece will break
Last Answer : (b) the magnetic lines of force will bend away from their usual paths in order to pass through the piece
Description : The direction of magnetic lines of force is (a) from south pole to north pole (b) from north pole to south pole (c) from one end of the magnet to another (d) none of the above
Last Answer : (b) from north pole to south pole
Description : A permeable substance is one (a) which is a good conductor (6) which is a bad conductor (c) which is a strong magnet (d) through which the magnetic lines of force can pass very easily
Last Answer : (d) through which the magnetic lines of force can pass very easily
Description : A current of 5.8 A flows through a 0.25 m long straight conductor which is kept perpendicular in a region of uniform magnetic field of 3.7 T . The force on conductor is a) 5.4 N b) 2.4 N c) 3.4 N d) 6.4 N
Last Answer : a) 5.4 N
Description : A magnetic screw placed in a non-uniform magnetic field experiences a) force and torque b) only torque c) only force d) None of these
Last Answer : a) force and torque
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 : Origin of the gravitational and electric forces: (a) is still unknown (b) was known in 1611 A.D (c) was known in 1712 A.D (d) was known in 1911 A.D
Last Answer : a) is still unknown
Description : Find the force that exists in an electromagnetic wave. a) Electrostatic force b) Magnetostatic force c) Lorentz force d) Electromotive force
Last Answer : c) Lorentz force
Description : Find the force experienced by an electromagnetic wave in a conductor? a) Electrostatic force b) Magneto static force c) Electro motive force d) Lorentz force
Last Answer : d) Lorentz force
Description : Lorentz force is based on, a) Dot product b) Cross product c) Both dot and cross product d) Independent of both
Last Answer : b) Cross product
Description : The negative sign in expression ɛ= -vBL shows that the angle between the direction of L and (v x B) is: a. 90 b. 180 c. 45 d. 0
Last Answer : a. 90
Description : Depletion region of a junction is formed _________ (a) during the manufacturing process (b) under forward bias (c) under reverse bias (d) when temperature varies
Last Answer : (a) during the manufacturing process
Description : Depletion region carries _________ (a) +ve charge (b) –ve charge (c) no charge (d) all of above
Last Answer : (c) no charge
Description : kWh meter is the electric meter that measures the amount of electrical _________ in kWh that was consumed in the house. (A) Energy (B) Current (C) Voltage (D) None of the above
Last Answer : kWh meter is the electric meter that measures the amount of electrical Energy in kWh that was consumed in the house.
Description : The Maxwell relation derived from the differential expression for the Helmholtz free energy (dA) is (A) (∂T/∂V)S = - (∂P/∂S)V (B) (∂S/∂P)T = - (∂V/∂T)P (C) (∂V/∂S)P = (∂T/∂P)S (D) (∂S/∂V)T = (∂P/∂T)V
Last Answer : (D) (∂S/∂V)T = (∂P/∂T)V
Description : A semiconductor formed by addition of trivalent impurity is : a) P–Type b) N–Type c) Q–type d) M–Type
Last Answer : d) M–Type
Last Answer : any Magnetic In the case A Isolated The answer To the pole In the free state Placement If you do The pole That Path Circulation By Him Magnetic Ball line Says.
Description : A material which is slightly repelled by a magnetic field is known as (a) ferromagnetic material (b) diamagnetic material (c) paramagnetic material (d) conducting material
Last Answer : (b) diamagnetic material
Description : Which of the following is a vector quantity ? (a) Relative permeability (b) Magnetic field intensity (c) Flux density (d) Magnetic potential
Last Answer : (b) Magnetic field intensity
Description : A magnetic field exists around (a) iron (b) copper (c) aluminium (d) moving charges
Last Answer : (d) moving charges
Description : What is a magnetic pick-up?*
Last Answer : An electromagnet used as a speed or position sensor.
Description : What is a relay? How is it different from a magnetic contactor?
Last Answer : Contactor is a heavy duty switch whereas the relay is light duty switch. Relays can be as simple as 12 V DC solenoids with 12 V, 0.5 A rated contacts. They are used to detect faults on the power system and signal a local or remote switching device (breaker) to trip the circuit.
Description : What is a magnetic contactor? Where is it used?
Last Answer : A contactor is an electrically controlled switch used for switching a power circuit, similar to a relay except with higher current ratings. Contactors are used to control electric motors, lighting, heating, capacitor banks, and other electrical loads.
Description : The branch of physics that deals with the investigation of wavelengths of electro magnetic radiation emitted or absorbed by atoms is known as a) spectroscopy b) astroscopy c) radioscopy d) stereoscopy
Last Answer : a) spectroscopy
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 windings of the electromagnetic are usually called: a. Magnetic coils b. Field coil c. Electric coil d. simple coil
Last Answer : c. Electric coil
Description : Magnetic flux linked with a coil can be changed by using an: a. Permanent magnet b.Bar magnet c. Electromagnet d. Horseshoe magnet
Last Answer : b.Bar magne
Description : The induced emf in a coil depends upon: a. Strength of magnetic field b. Resistance of the coil c. area of the coil d. All of them
Last Answer : d. All of them
Description : Which of the following will produce an induced emf: a. Changing area of coil b. Changing magnetic flux c. changing orientation of coil d. all of them
Last Answer : c. changing orientation of coil
Description : The induced current can be increased by: a. Using strong magnetic field b. moving loop faster c. Replacing loop by coil d. all of above
Last Answer : d. all of above
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 : If magnetic field is doubled then magnetic energy density becomes: a. Four times b. Two times c. Three times d. Six times
Last Answer : c. Three times
Description : Electric current produces magnetic field was suggested by: a. Faraday b. Lenz c. Ohm d. Oerested
Last Answer : c. Ohm
Description : A wire loop is moved parallel to a uniform magnetic field. The induced emf in the loop: a. depends on the shape b. depends on area c. depends on nature of loop d. zero
Last Answer : d. zero
Description : The current flowing in a coil due to induced emf depends upon: a. shape of coil b. resistance of coil c. area of coil d. magnetic flux
Last Answer : a. shape of coil
Description : If velocity of a conductor moving through a magnetic field ‘B’ is made zero, then Motional emf will be: a. –VBL b. –V/BL c. – BL/V d. zero
Last Answer : a. –VBL
Description : The induced emf is produced in a circuit due to: a. Initial magnetic flux b. final magnetic flux c. Change of magnetic flux d. constant magnetic flux
Last Answer : d. constant magnetic flux