NEET 2025 Solutions
NEET Physics (2025)

The electric field in a plane electromagnetic wave is given by $E_z = 60\cos(5x + 1.5 \times 10^9 t)\ \text{V/m}$. Then expression for the corresponding magnetic field is (here subscripts denote the direction of the field):

An electron (mass $= 9 \times 10^{-31}\ \text{kg}$ and charge $= 1.6 \times 10^{-19}\ \text{C}$) moving with speed $c/100$ ($c =$ speed of light) is injected into a magnetic field $\vec{B}$ of magnitude $9 \times 10^{-4}\ \text{T}$ perpendicular to its direction of motion. We wish to apply a uniform electric field $\vec{E}$ together with the magnetic field so that the electron does not deflect from its path. Then: (speed of light $c = 3 \times 10^8\ \text{ms}^{-1}$)

Two gases A and B are filled at the same pressure in separate cylinders with movable pistons of radius $r_A$ and $r_B$, respectively. On supplying an equal amount of heat to both the systems reversibly under constant pressure, the pistons of gas A and B are displaced by 16 cm and 9 cm, respectively. If the change in their internal energy is the same, then the ratio $\dfrac{r_A}{r_B}$ is equal to:

Three identical heat conducting rods are connected in series as shown in the figure. The rods on the sides have thermal conductivity $2K$ while that in the middle has thermal conductivity $K$. The left end is at $3T$ and right end at $T$. In steady state, the temperatures at the junctions are $T_1$ (left) and $T_2$ (right). The ratio $T_1/T_2$ is:\n\n