Electromagnetic-Induction-Quiz-7

Electromagnetic Induction Quiz-7

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. 

Q61. A horizontal rod of length L rotates about a vertical axis with a uniform angular velocity ω.A uniform magnetic field B exists parallel to the axis of rotation. Then potential difference between the to ends of the rod

•  ωL² B
•  ω² LB
•  1/2 ωL² B
•  1/2 ω² LB

Solution
                     

Q62.Which of the following is a wrong statement

•  An emf can be induced between the ends of a straight conductor by moving it through a uniform magnetic field
•  The self induced emf produced by changing current in a coil always tends to decrease the current
•  Inserting an iron core in a coil increases its coefficient of self induction
•  According to Lenz’s law, the direction of the induced current is such that it opposes the flux change that causes it

Solution
The self induced emf produced by changing current in a coil always tends to decrease the current

Q63.  A transformer rated at 10k W is used to connect a 5 kV transmission line to a 240 V circuit. The ratio of turns in the windings of the transformer is

•   5
•  20.8
•  104
•  40

Solution
                            

Q64. A coil having an area A₀ is placed in a magnetic field which changes from B₀ to 4B₀ in a time interval t. The e.m.f. induced in the coil will be

•  (3A₀ B₀ )/t
•  (4A₀ B₀)/t
•  (3B₀)/(A₀ t)
•  (4B₀)/(A₀ t)

Solution
                         

Q65.If a charge in current of 0.01 A in one coil produces a change in magnetic flux of 1.2×10^-2 Wb in the other coil, then the mutual inductance of the two coils in henry is

•  0
•  0.5
•  1.2
•  3

Solution
                         

Q66. As shown in the figure, a magnet is moved with a fast speed towards a coil at rest. Due to this induced electromotive force, induced current and induced charge in the coil is E,I and Q respectively. If the speed of the magnet is doubled, the incorrect statement is

•  E increases
• I increases
•  Q remains same
•  Q increases

Solution
Induced charge doesn’t depend upon the speed of magnet

Q67.Eddy currents are produced when

•  A metal is kept in varying magnetic field
•  A metal is kept in the steady magnetic field
•  A circular coil is placed in a magnetic field
•  Through a circular coil, current is passed

Solution
A metal is kept in varying magnetic field

Q68.A coil having 500 square loops each of side 10 cm is placed normal to a magnetic field which increases at the rate of 1 Wm^-2. The induced emf is

•  0.1 V
•  5.0 V
•  0.5 V
•  1.0 V

Solution
                         

Q69.A coil and a bulb are connected in series with a dc source, a soft iron core is then inserted in the coil. Then

•  Intensity of the bulb remains the same
•  Intensity of the bulb decreases
•  Intensity of the bulb increases
•  The bulb ceases to glow

Solution
there will be self induction effect when soft iron core is inserted

Q70. The north pole of a long bar magnet was pushed slowly into a short solenoid connected to a galvanometer. The magnet was held stationary for a few seconds with the north pole in the middle of the solenoid and then withdrawn rapidly. The maximum deflection of the galvanometer was observed when the magnet was

•  Moving towards the solenoid
•  Moving into the solenoid
•  At rest inside the solenoid
•  Moving out of the solenoid

Solution
More rapid is the movement of bar magnet, more is the deflection observed in the galvanometere of induced emf dϕ/dt=12 V