When a rectangular coil is rotated in a uniform magnetic field about an axis passing through its centre and perpendicular to the field,the emf induced in the coil varies

An elliptical loop having resistance $R$,semi-major axis $a$,and semi-minor axis $b$ is placed in a magnetic field as shown in the figure. If the loop is rotated about the $x$-axis with angular frequency $\omega$,the average power loss in the loop due to Joule heating is:

$A$ square-shaped coil of area $70 \, cm^2$ having $600$ turns rotates in a magnetic field of $0.4 \, Wb/m^2$,about an axis which is parallel to one of the sides of the coil and perpendicular to the direction of the field. If the coil completes $500$ revolutions in a minute,the instantaneous emf when the plane of the coil is inclined at $60^{\circ}$ with the field will be $..........V$. (Take $\pi = \frac{22}{7}$)

The phase difference between the magnetic flux linked with a coil rotating in a uniform magnetic field and the induced $e.m.f.$ produced in it is

$A$ ring of resistance $10 \Omega$,radius $10 \text{ cm}$,and $100$ turns is rotated at a rate of $100$ revolutions per second about a fixed axis which is perpendicular to a uniform magnetic field of induction $10 \text{ mT}$. The amplitude of the current in the loop will be nearly $A$ (Take $\pi^2 = 10$).

$A$ circular coil of mean radius $7 \, cm$ and having $4000$ turns is rotated at the rate of $1800$ revolutions per minute in the earth's magnetic field $(B = 0.5 \, \text{gauss})$. The maximum $e.m.f.$ induced in the coil will be .... $V$.