MCQ
A thermos flask is polished well
  • A
    To make attractive
  • B
    For shining
  • C
    To absorb all radiations from outside
  • To reflect all radiations from outside

Answer

Correct option: D.
To reflect all radiations from outside
(d) The polished surface reflects all the radiation.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Consider an optical communication system operating at $\lambda 800 \mathrm{~nm}$. Suppose, only $1 \%$ of the optical source frequency is the available channel bandwidth for optical communication. How many channels can be accommodated for transmitting audio signals requiring a bandwidth of $8 \mathrm{kHz}$
Dimensional formula for angular momentum is
A train is moving towards east and a car is along north, both with same speed. The observed direction of car to the passenger in the train is
Two bodies moving towards each other collide and move away in opposite directions. There is some rise in temperature of bodies because a part of the kinetic energy is converted into
The mass of the electron varies with
A particle moves towards east with velocity $5 m / s$. After 10 seconds its direction changes towards north with same velocity. The average acceleration of the particle is
A black body emits radiations of maximum intensity at a wavelength of $5000 \mathring A$, when the temperature of the body is $1227^{\circ} \mathrm{C}$. If the temperature of the body is increased by $1000^{\circ} \mathrm{C}$, the maximum intensity of emitted radiation would be observed at
Lenz's law is consequence of the law of conservation of
The thermal capacity of $40 \mathrm{gm}$ of aluminium (specific heat $=0.2$ $\left.\mathrm{cal} / \mathrm{gm} /{ }^{\circ} \mathrm{C}\right)$ is
A semiconductor $X$ is made by doping a germanium crystal with arsenic $(Z=33)$. A second semiconductor $Y$ is made by doping germanium with indium $(Z=49)$. The two are joined end to end and connected to a battery as shown. Which of the following statements is correct