NTA JEE Mains 24th Jan 2025 Shift 2

The temperature of a body in air falls from $$ 40^{o}C $$ to $$ 24^{o}C $$ in 4 minutes. The temperature of the air is $$ 16^{o}C $$. The temperature of the body in the next 4 minutes will be:

A solid sphere is rolling without slipping on a horizontal plane. The ratio of the linear kinetic energy of the centre of mass of the sphere and rotational kinetic energy is :

In a Young's double slit experiment, three polarizers are kept as shown in the figure. The transmission axes of  $$P_1$$  and  $$P_2$$ are orthogonal to each other. The polarizer  $$P_3$$  covers both the slits with its transmission axis at  $$45^\circ$$  to those of  $$P_1$$  and  $$P_2$$. An unpolarized light of wavelength  $$\lambda$$ and intensity  $$I_0$$  is incident on  $$P_1$$  and  $$P_2$$.The intensity at a point after  $$P_3$$  where the path difference between the light waves from $$s_1$$  and  $$s_2$$  is  $$\frac{\lambda}{3}\text{ is:}$$

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : In an insulated container, a gas is adiabatically shrunk to half of its initial volume. The temperature of the gas decreases. Reason (R): Free expansion of an ideal gas is an irreversible and an adiabatic process. In the light of the above statements, choose the correct answer from the options given below :

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : A electron in a certain region of uniform magnetic field is moving with constant velocity in a straight line path. Reason (R): The magnetic field in that region is along the direction of velocity of the electron. In the light of the above statements, choose the correct answer from the options given below :

The ratio of the power of a light source  $$S_1$$ to that of the light source $$S_2$$ is  2.$$S_1$$ is emitting  $$2\times10^{15}$$ photons per second at  600,nm. If the wavelength of the source  $$S_2$$  is  300, nm,then the number of photons per second emitted by  $$S_2$$ is $$\underline {\hspace{2cm}}$$ $$\times 10^{14}.$$

$$\text{A string of length } L \text{ is fixed at one end and carries a mass of } M\text{ at the other end. }\text{The mass makes } \left(\frac{3}{\pi}\right)\text{ rotations per second about the vertical axis passing through end of the string as shown. }\text{The tension in the string is } \underline{\hspace{2cm}} ML.$$

The increase in pressure required to decrease the volume of a water sample by  $$0.2%$$  is  $$P \times10^5\,Nm^{-2}.$$ Bulk modulus of water is  $$2.15\times10^9\,Nm^{-2}.$$  The value of  $$P$$  is  $$\underline{\hspace{2cm}}.$$

A tightly wound long solenoid carries a current of  $$1.5\,A.$$ An electron is executing uniform circular motion inside the solenoid with a time period of  $$75\,ns.$$ The number of turns per metre in the solenoid is $$\underline{\hspace{1cm}}.$$ [Take mass of electron  $$m_e=9\times10^{-31}\,kg,$$  change of electron $$|q_e|=1.6\times10^{-19}\,$$ $$C,$$ $$\mu_0=4\pi\times10^{-7}\,N$$ $$A^{-2},\,1\,ns=10^{-9}\,s]$$

Acceleration due to gravity on the surface of earth is  $$g$$. If the diameter of earth is reduced to one third of its original value and mass remains unchanged, then the acceleration due to gravity on the surface of the earth is $$\underline{\hspace{2cm}}\,g.$$