1
WB JEE 2025
MCQ (Single Correct Answer)
+2
-0.5
Change Language

$10^{20}$ photons of wavelength 660 nm are emitted per second from a lamp. The wattage of the lamp is (Planck's constant $=6.6 \times 10^{-34} \mathrm{Js}$ )

A
30 W
B
60 W
C
100 W
D
500 W
2
WB JEE 2025
MCQ (Single Correct Answer)
+2
-0.5
Change Language

The apparent coefficient of expansion of a liquid, when heated in a copper vessel is $C$ and when heated in silver vessel is $S$. If $A$ is linear coefficient of expansion of copper, then linear coefficient of expansion of silver is

A
$\frac{C-S-3 A}{3}$
B
$\frac{C+3 A-S}{3}$
C
$\frac{S+3 A-C}{3}$
D
$\frac{C+S+3 A}{3}$
3
WB JEE 2025
MCQ (Single Correct Answer)
+2
-0.5
Change Language

The equation of a stationary wave along a stretched string is given by $y=5 \sin \frac{\pi x}{3} \cos 40 \pi t$. Here $x$ and $y$ are in cm and $t$ in second. The separation between two adjacent nodes is

A
1.5 cm
B
3 cm
C
6 cm
D
14 cm
4
WB JEE 2025
MCQ (Single Correct Answer)
+2
-0.5
Change Language

Temperature of a body $\theta$ is slightly more than the temperature of the surrounding $\theta_0$. Its rate of cooling $(R)$ versus temperature of the body $(\theta)$ is plotted. Its shape would be

A
WB JEE 2025 Physics - Heat and Thermodynamics Question 1 English Option 1
B
WB JEE 2025 Physics - Heat and Thermodynamics Question 1 English Option 2
C
WB JEE 2025 Physics - Heat and Thermodynamics Question 1 English Option 3
D
WB JEE 2025 Physics - Heat and Thermodynamics Question 1 English Option 4
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