Magnetism and M...

The magnetic flux $$\phi$$ (in weber) in a closed circuit of resistance $$10\ ohm$$ varies with time $$t$$ (in second) according to equation $$\phi=6t^{2}-5t+1$$. The magnitude of induced current at $$t=0.25\ s$$ is:

Which diagram shows the magnetic field around a bar magnet?

Needles $$N_1, N_2$$ and $$N_3$$ are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will?

The magnetic flux linked with a coil varies as $$\phi =3t^2+4t+9$$. The magnitude of the emf induced at $$t=2$$ seconds is?

A jet plane having a wing-span of $$25$$ m is travelling horizontally towards east with a speed of $$3600$$ km/hour. If the Earth's magnetic field at the location is $$4\times 10^{-4}$$T and the angle of dip is $$30^o$$, then, the potential difference between the ends of the wing is?

Curies temperature is the temperature above which :

The diagram shows the magnetic field around two bar magnets. Which diagram shows the poles of the magnets?

A constant current $$I_{0}$$ is passing through a long straight wire (shown in figure).
A rectangular loop of total resistance $$R$$ is moving parallel to the wire. Then:

A conducting ring is placed around the core of an electromagnet as shown in figure. When key $$K$$ is pressed, the ring :

Mark correct option or options :