UPSC Geo Scientist 2025 Prelims Paper I (General Studies) Question Paper (09-Feb-2025)

Question 1

An electromagnetic wave with its magnetic field $B = 0.3\cos(ky-10^8t)i$ tesla is propagating in a non-magnetic dielectric medium of refractive index 2. The wavelength of the wave is

Accepted Answer

3$\pi$ m

Answer

6$\pi$ m

Answer

0.3 m

Answer

(2$\pi$/3) m

Question 2

A spherical conductor of radius $a$ has a cavity of radius $b$ at its centre such that $a > b$. A positive charge $q$ is placed at its centre (see in the figure). The electric fields in the regions $b < r<a$ and $r > a$ are respectively

Accepted Answer

zero and $\frac{q}{4\pi\epsilon_0r^2}$ outward

Answer

$\frac{q}{4\pi\epsilon_0a^2}$ inward and $\frac{q}{4\pi\epsilon_0b^2}$ outward

Answer

zero and zero

Answer

$\frac{q}{4\pi\epsilon_0r^2}$ inward and zero

Question 3

For a given system of resistors having resistances R, 2R, R$_0$ and 2R (shown in the figure), what will be the value of resistance of the resistor R$_0$, when there is NO current in the galvanometer G?

Accepted Answer

R$_0$ = 4R

Answer

R$_0$ = 0

Answer

R$_0$ = R

Answer

R$_0$ = 2R

Question 4

A cyclotron has an oscillator frequency of $12	imes10^6$ Hz and 'Dee' radius of 21 inches. The value of magnetic induction (field) needed to accelerate a deuteron (mass = $3.34 	imes 10^{-27}$ kg and charge = $1.6	imes10^{-19}$ C) is

Accepted Answer

1.573 tesla

Answer

157.3 tesla

Answer

15.73 tesla

Answer

0.157 tesla

Question 5

When white light propagating in air passes through a glass prism, it splits into a band of colours referred to as the white light spectrum. This phenomenon is called the dispersion of light. Among the following colours, the angle of deviation will be the highest in

Accepted Answer

green

Answer

yellow

Answer

orange

Answer

red