Question

SECTION - (B)
Questions 15 and 16 are case study based questions and are compulsory. Attempt any 4 parts from
each questions. Each question carries 1 mark.
15 Deepak's sister was using washing machine and being in hurry, put few clothes inside the machine. The
machine could not be started. It was observed that the lid had not closed properly. Even on taking out the extra
clothes from the machine, the lid did not close. Deepak was requested to help her but he also could not
succeed. On closer observation, Deepak observed that the mechanism of lid closure was of a different nature
and not mechanical. He went through the machine's user manual and found that it was a different mechanism
and had to be replaced. He later bought a magnetic lid closer and replaced the old one. The machine started
working Sister expressed her thanks to Deepak.
(1) Which of the Physics concept is used in functioning of door/lid closers of electric devices used commonly:
(a) Electric door closer system
(b) Magnetic door closer system
(c) Both a & b
(d) None of these
Name any one other common devices in which this concept is used.
Which of the values are reflected in Deepak's behavior and actions ?
(a) Curiosity (b) Scientific temper (c) Sprit of enquiry (d) All of these
(IV)
The Torque on a magnetic dipole (door/lid) in a uniform magnetic field is:
(a) T = mBsino (b) T = mBcose (C) T = - mBsino (d) T = -mBcoso
(V)
The potential energy of a magnetic dipole (door/lid) in a uniform magnetic field is:
(a) U = -mBcose (b) U = mBcose (c) U = -mBsine (d) U = mBsino​

Answer 1

Potential energy of a magnetic dipole in a magnetic field. done is equal to the decrease in potential energy of the system, i.e., dU = −dW = µBsinθ. ... the potential energy of a magnetic dipole at angle θ to the direction of a magnetic field.....

✨⚔️hope it helps⚡⚔️