The sun emits a light with maximum wavelength $510\, mm$ while another star $X$ emits a light with maximum wavelength of $350\, nm$. What is the ratio of surface temperature of sun and the star $X$
A$2.1$
B$0.68$
C$0.46$
D$1.45$
AIIMS 2000, Medium
Download our app for free and get started
B$0.68$
b (b)As $\lambda \propto \frac{1}{T};$ so $\frac{{{T_1}}}{{{T_2}}} = \frac{{{\lambda _2}}}{{{\lambda _1}}} = \frac{{350}}{{510}} = 0.68$
Download our app
and get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
Two materials having coefficients of thermal conductivity $3K$ and $K$ and thickness $d$ and $3d$, respectively, are joined to form a slab as shown in the figure. The temperatures of the outer surfaces are $\theta_2$ and $\theta_1$ respectively $\left( {\theta _2} > {\theta _1} \right)$ . The temperature at the interface is
The two ends of a rod of length $L$ and a uniform cross-sectional area $A$ are kept at two temperatures $T_1$ and $T_2 (T_1 > T_2)$. The rate of heat transfer,$\frac{ dQ }{dt}$, through the rod in a steady state is given by
If a piece of metal is heated to temperature $\theta$ and then allowed to cool in a room which is at temperature $\theta_0$, the graph between the temperature $T$ of the metal and time t will be closest to
Two spheres of same material have radius $1m$ and $4 m$ and temperature $4000K$ and $2000K$ respectively. The energy radiated per second by the first sphere is
A black body at a temperature of $1640\,\,K$ has the wavelength corresponding to maximum emission equal to $1.75 \,\,\mu m.$ Assuming the moon to be a perfectly black body, the temperature of the moon, if the wavelength corresponding to maximum emission is $14.35\,\,\mu m$ is.......$K$
A metal rod of length $2\, m$ has cross-sectional areas $2A$ and $A$ as shown in the following figure. The two ends are maintained at temperatures $100\,^oC$ and $70\,^oC$. The temperature of middle point $C$ is ........ $^oC$