Electromagnetic Induction · Physics · MHT CET (Biology)
MCQ (Single Correct Answer)
Two coils having self-inductances $\mathrm{L}_1=75 \mathrm{mH}$ and $L_2=48 \mathrm{mH}$ are coupled with each other. If the mutual inductance of the coils is 37.2 mH , then coefficient of coupling will be
An elastic conducting material is stretched into a circular loop. It is placed with its plane perpendicular to uniform magnetic field $\mathrm{B}=0.6 \mathrm{~T}$. When loop is released, the radius starts shrinking at constant rate $3 \mathrm{~cm} / \mathrm{s}$. The induced e.m.f. in the loop at an instant when the radius of the loop is 10 cm will be (in mV )
Two inductors of 88 mH each are joined in parallel. The current passing through this combination is 4 A . The energy stored in this combination of inductors in joule is
A bicycle wheel of diameter ' $D$ ' has ' $N$ ' number of spokes. Wheel is rotating at the rate of ' $x$ ' revolutions per minute, perpendicular to the horizontal component of earth's magnetic field ' $\mathrm{B}_{\mathrm{H}}$ '. The e.m.f. induced between the rim and the centre of the wheel will be
If current ' i ' is passing through the solenoid of diameter ' $d$ ' having number of turns per unit length ' $n$ ', then the inductance per unit length near the middle of a long solenoid is directly proportional to
The flux linked with the coil at any instant ' t ' is given by $\phi=12 t^2-60 t+275$. The magnitude of induced e.m.f. at $\mathrm{t}=3 \mathrm{~second}$ is
A coil of area $12 \mathrm{~cm}^2$ has 250 turns. Magnetic field of $0.2 \mathrm{~Wb} / \mathrm{m}^2$ is perpendicular to the plane of the coil. The field is reduced to $0.1 \mathrm{~Wb} / \mathrm{m}^2$ in 0.1 second. The magnitude of induced e.m.f. in the coil is
Two different coils have self - inductance $\mathrm{L}_1=9 \mathrm{mH}$ and $\mathrm{L}_2=3 \mathrm{mH}$. The current in first coil is increased at a constant rate. The current in the second coil is also increased at the same constant rate. At certain instant of time, the power given to the two coils is same. At that time, there was current and induced voltage in the two coils. At the same instant, the ratio of the energy stored in the first coil to that in second coil is
Figure shows a rectangular frame situated in a constant magnetic field. A wire BC of length 1 m is moved out with velocity $4 \mathrm{~m} / \mathrm{s}$. Magnetic field strength is 0.15 T . Force acting on the wire $B C$ is
