MAGNETISM AND MATTER Quiz-15
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. A magnetic needle is kept in a non-uniform magnetic field. It experiences force and torque both due to unequal forces acting on poles.
Solution
Magnetic needle is placed in non-uniform magnetic field. It experience force and torque both due to unequal forces acting on poles.
Magnetic needle is placed in non-uniform magnetic field. It experience force and torque both due to unequal forces acting on poles.
Q2. The value of the horizontal component of the earth’s magnetic field and angle of dip are 1.8×10-5 weber/m2 and 30° respectively at some place. The total intensity of earth’s magnetic field at that place will be
Solution
Q3. The torque on a bar magnet due to the earth magnetic field is maximum when the axis of the magnet is
Solution
Torque on a bar magnet in earths magnetic field BH is Ï„=MBH sinθ.Ï„ will be maximum if sinθ= maximum i.e.θ=90°. Hence axis of the magnet is perpendicular to the field of earth
Torque on a bar magnet in earths magnetic field BH is Ï„=MBH sinθ.Ï„ will be maximum if sinθ= maximum i.e.θ=90°. Hence axis of the magnet is perpendicular to the field of earth
Q4. If the magnetic is cut into four equal parts such that their lengths and breadths are equal. Pole strength of each part is
Solution
Q5.Two equal bar magnets are kept as shown in the figure. The direction of resultant magnetic field, indicated by arrow head at the point P is (approximately) 
Solution
It is a fact.
It is a fact.
Q6. A bar magnet of length 10 cm and having pole strength equal to 10-3 Wb is kept in a magnetic field having magnetic induction B equal to 4Ï€×10-3T. It makes an angle of 30° with the direction of magnetic induction. The value f the torque acting on the magnet is
Solution
In SI unit of pole strength is Amp-meter. Here, the pole strength is given in Weber, which is the unit of (μ0 m). ∴μ0 m=10-3Wb m=10-3/μ0 Magnetic moment of magnet M=m×2l=10-3/μ0 (0.1)=10-4/μ0. Torque, Ï„=MBsinθ =10-4/(4Ï€×10-7 ) (4Ï€×10-3 )×1/2=0.5 Nm
In SI unit of pole strength is Amp-meter. Here, the pole strength is given in Weber, which is the unit of (μ0 m). ∴μ0 m=10-3Wb m=10-3/μ0 Magnetic moment of magnet M=m×2l=10-3/μ0 (0.1)=10-4/μ0. Torque, Ï„=MBsinθ =10-4/(4Ï€×10-7 ) (4Ï€×10-3 )×1/2=0.5 Nm
Q7.The magnetising field required to be applied in opposite direction to reduce residual magnetism to zero is called
Solution
This magnetising field is a measure of coercivity of the material.
This magnetising field is a measure of coercivity of the material.
Q8.A paramagnetic liquid is taken in a U-tube and arranged so that one of its limbs is kept between pole pieces of the magnet. The liquid level in the limb
Solution
When a paramagnetic liquid is taken in U-tube and one arm is placed between the poles of strong magnet, the liquid is feebly attracted by the magnet. Therefore, the level of the solution in the arm rises.
When a paramagnetic liquid is taken in U-tube and one arm is placed between the poles of strong magnet, the liquid is feebly attracted by the magnet. Therefore, the level of the solution in the arm rises.
Q9.A bar magnet is oscillating in the Earth’s magnetic field with a period T. What happens to its period of motion if its mass is quadrupled?
Solution
When mass is quadrupled, ie, made 4 times. Ibecomes four times. As T∝√I. ∴Tbecomes twice, ie, motion remains SHM with time period =2T.
When mass is quadrupled, ie, made 4 times. Ibecomes four times. As T∝√I. ∴Tbecomes twice, ie, motion remains SHM with time period =2T.
Q10. For substances hysteresis (B-H) curves are given as shown in figure. For making temporary magnet which of the following is best
Solution
For a temporary magnet the hysteresis loop should be long and narrow
For a temporary magnet the hysteresis loop should be long and narrow
