Quiz-14-magnetic-effect-of-current-&-magnetism

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MAGNETISM AND MATTER Quiz-14

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. .

Q1. Two bar magnets of the same mass, same length and breadth but having magnetic moments M and 3M are joined together pole for pole and suspended by a string. The time period of assembly in a magnetic field of strength H is 3 s. If now the polarity of one of the magnets is reversed and the combination is again made to oscillate in the same field, the time of oscillation is

•  3 s
•  3√3 s
•  3/√3 s
•  6 s

Solution

Q2. A magnet of magnetic moment M is rotated through 360° in a magnetic field H. The work done will be

•  MH
•  2MH
•  2πMH
•  Zero

Solution
W=MB(cos⁡θ₁-cos⁡θ₂); θ₁=0° and θ₂=360°⇒W=0

Q3. A coil of 50 turns and area 1.25×10^-3 m² is pivoted about a vertical diameter in a uniform horizontal magnetic field and carries a current of 2 A. When the coil is held with its plane is N-S of 2A. When the coil is held with its plane in N-S direction, it experience a couple of 0.04 N-m; and when its plane is E-W, the corresponding couple is 0.03 N-m. The magnetic induction is

•  0.2 T
•  0.3 T
•  0.4 T
•  0.5 T

Solution

Q4. A short bar magnet has a length 2l and a magnetic moment 10 Am². Find the magnetic field at a distance of z=0.1 m from its centre on the axial line. Here, l is negligible as compared to z.

•  2×10^-3 T
•  3×10^-3 T
•  1×10^-3 T
•  4×10^-3 T

Solution

Q5.Lines which represent places of constant angle of dip are called

•  Isobaric lines
•  Isogonic lines
•  Isoclinic lines
•  Isodynamic lines

Solution
 It is a fact.

Q6. Two identical short bar magnets, each having magnetic moment M, are placed a distance of 2d apart with axes perpendicular to each other in a horizontal plane. The magnetic induction at a point midway between them is

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Solution

Q7.The distance of two points on the axis of a magnet from its centre is 10 cm and 20 cm respectively. The ratio of magnetic intensity at these points is 12.5∶1. The length of the magnet will be

•  5 cm
•  25 cm
•  10 cm
•  20 cm

Solution

Q8.The time period of oscillation of a freely suspended bar magnet with usual notations is given by

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•  
  
  
  

Solution
It is a fact.

Q9.The force between two magnetic poles is F. If the distance between the poles and pole strengths of each pole are doubled, then the force experienced is

•  2F
•  F/2
•  F/4
•  F

Solution

Q10. When a ferromagnetic material is heated to temperature above its curie point, the material

•  Is permanently magnetized
•  Remains ferromagnetic
•  Behaves like a diamagnetic material
• Behaves like a paramagnetic material

Solution
Ferromagnetic substance are strongly attracted by a magnet, show all properties of a paramagnetic substance to a much higher degree. While paramagnetic substances are feebly attracted by a magnet. When ferromagnetic substance is heated, then at a definite temperature the ferromagnetic property of the substance suddenly disappears and the substance becomes paramagnetic. The temperature above which a ferromagnetic substance becomes paramagnetic is called the curie temperature (point) of the substance.