Electromagnetic-Induction-Quiz-4

Electromagnetic Induction Quiz-4

Dear Readers,

As per analysis for previous years, it has been observed that students preparing for NEET find Physics out of all the sections to be complex to handle and the majority of them are not able to comprehend the reason behind it. This problem arises especially because these aspirants appearing for the examination are more inclined to have a keen interest in Biology due to their medical background. 

Furthermore, sections such as Physics are dominantly based on theories, laws, numerical in comparison to a section of Biology which is more of fact-based, life sciences, and includes substantial explanations. By using the table given below, you easily and directly access to the topics and respective links of MCQs. Moreover, to make learning smooth and efficient, all the questions come with their supportive solutions to make utilization of time even more productive. Students will be covered for all their studies as the topics are available from basics to even the most advanced. 

Q31. If rotational velocity of a dynamo armature is doubled, then induced e.m.f. will become

•  Half
•  Two times
•  Four times
•  Unchanged

Solution
e∝ω

Q32.Consider the statements:
(I)If magnetic field, B =0, then magnetic flux is also zero.
(II)If magnetic flux, ϕ=0,then magnetic field is also zero.

•  Cyclotron
•  Betatron
•  Van de Graff generator
•  Cockroft- Walton generator

Solution
Betatron uses the phenomenon of electromagnetic induction.

Q33.  The direction of induced current is such that it opposes the very cause that has produced it. This is the law of

•  Lenz
•   Faraday
•  Kirchhoff
•  Fleming

Solution
Lenz

Q34. In an AC generator, a coil with N turns, all of the same area A and total resistance R, rotates with frequency ω in a magnetic field B. The maximum value of emf generated in the coil is

•  NABRω
•  NAB
•  NABR
•  NABω

Solution
                   

Q35.Large transformers, when used for some time, become hot and are cooled by circulating oil. The heating of transformer is due to

•  Heating effect of current alone
•  Hysteresis loss alone
•  Both the hysteresis loss and heating effect of current
•  None of the above

Solution
  Both the hysteresis loss and heating effect of current

Q36. In a transformer 220 ac voltage is increased to 2200 volts. If the number of turns in the secondary are 2000, then the number of turns in the primary will be

•  200
•  100
• 50
•  20

Solution
                      

Q37.The coils of a step down transformer have 500 and 5000 turns. In the primary coil an ac of 4 ampere at 2200 volts is sent. The value of the current and potential difference in the secondary coil will be

•  20 A,220 V
•  0.4 A,22000 V
•  40 A,220 V
•  40 A,22000 V

Solution
                       

Q38.A coil is suspended in a uniform magnetic field, with the plane of the coil parallel to the magnetic lines of force. When a current is passed through the coil it starts oscillating; it is very difficult to stop. But if an aluminium plate is placed near to the coil, it stops. This is due to

•  Development of air current when the plate is placed
•  Induction of electrical charge on the plate
•  Shielding of magnetic lines of force as aluminium is a paramagnetic material
•  Electromagnetic induction in the aluminium plate giving rise to electromagnetic damping

Solution
Electromagnetic induction in the aluminium plate giving rise to electromagnetic damping

Q39.When a battery is connected across a series combination of self inductance L and Resistance R, the variation in the current i with time t is best represented by

•  
  
  
•  
  
  
•  
  
  
•  
  
  

Solution
                      

Q40. A wire of length 50 cm moves with a velocity of 300 m-min^-1, perpendicular to a magnetic field. If the emf induced in the wire is 2 V, the magnitude of the field in telsa is

•  2
•  5
• 0.4
•  0.8

Solution