The temperature at which the thermo-electric power of a thermocouple becomes zero is called:

The current flowing along the path $A B C D$ of a cube (shown in the left figure) produces a magnetic field at the centre of the cube of magnitude $B$. Dashed lines depict the non-conducting part of the cube. Consider a cubical shape shown to the right which is identical in size and shape to the left. If the same current now flows in along the path $D A E F G C D$,then the magnitude of the magnetic field at the centre will be

$A$ particle of charge $q$ and mass $m$ is moving along the $x$-axis with a velocity $v$ and enters a region of electric field $E$ and magnetic field $B$ as shown in the figures below. For which figure may the net force on the charge be zero?

In a Thomson mass spectrograph,the electric field and magnetic field are applied:

$A$ beam of electrons and protons move parallel to each other in the same direction. Then they:

$A$ loop of irregular shape made of flexible conducting wire carrying a clockwise current is placed in a uniform inward magnetic field,such that its plane is perpendicular to the field. Then the loop: