The magnetic field of a light wave at given time parallel to y-axis and is given by \( B = B_m \sin(kz - \omega t) \). In what direction does the wave travel and parallel to which axis does the associated electric field point at that time?

A piece of copper and a piece of germanium are cooled from room temperature 20 C down to 80 K. The resistance of

Two galvanometers have identical characteristics. One of them is converted into a milliammeter and the other into a microammeter. The shunt resistance of microammeter as compared to milliammeter will be :

Two wires of equal lengths carrying equal currents bent in the form of two loops, one in square shape and the other in circular shape having one turn only are suspended in same, uniform magnetic field perpendicular to the plane of loops. Choose the correct option

The electric field and magnetic field of a plane electromagnetic wave propagating in vacuum are expressed as
\(E_x=E_0 \sin (k z-\omega t)\)
\(B_y=B_0 \sin (k z-\omega t)\)
Which of the following statements are correct?
(A). The wave is propagating along the z- direction.
(B). The electric field Ex and magnetic field By are perpendicular to each other and perpendicular to the z direction.
(C) The electric and magnetic fields Ex and By are perpendicular to each other, and parallel to the direction of propagation.
(D) k is related to the wave length À of the wave by the usual equation \(k = A / 2 Tt\)
Choose the correct answer from the options given below:

The energy of a photon of wavelength (\( \lambda \)) is given by the expression: (Symbols have their usual meaning: h = Planck's constant, c = speed of light)

The focal length of the objective of a microscope is \( f_o \) and that of the eye piece is \( f_e \). The aperture of objective is \( d_o \) and that of eye piece is \( d_e \). Which of the following relation is correct ?

A proton moving with a constant velocity passes through a region without any change in its velocity. Then in this region :

If v is the frequency of ac mains, then the frequency of sonometer wire at resonance is :

Two infinitely long parallel conductors carrying currents I 1 and I 2 are at distance d apart. The force \(F\) on length \(L\) of one conductor due to the other is :

Out of the following which will be see-saw shaped?
A. \(\text{XeO}_2\text{F}_2\)
B. \(\text{SF}_4\)
C. \(\text{BrF}_3\)
D. \(\text{XeO}_4\)
Choose the correct answer from the options given below:

If A is a square matrix such that \(A^2=A\), then \(|A|\) equals :

The value of \(\lambda\), so that the lines \(\frac{1-x}{3}=\frac{7 y-14}{2 \lambda}=\frac{z-3}{2}\) and \(\frac{7-7 x}{3 \lambda}=\frac{y-5}{1}=\frac{6-z}{5}\) are perpendicular is: