Lux is the SI unit of
On a rainy day, small oil films on water show brilliant colours. This is due to
Point A is at a lower electrical potential than point B. An electron between them on the line joining them will
RADAR is used for
Materials for rain-proof coats and tents owe their water-proof properties to
Sound of frequency below 20 Hz is called
On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because
Suitable impurities are added to a semiconductor depending on its use. This is done in order to
Stars twinkle because
It takes much longer to cook food in the hills than in the plains, because
Moment of inertia is
Of the following natural phenomena, tell which one known in Sanskrit as 'deer's thirst'?
Inside an aeroplane, flying at a high altitude,
Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?
One thousand microns is equal to
Sound travels at the fastest speed in
oil raise up the wick in a lamp. The principle involves
Superconductors are substances which
Light travels at the fastest speed in
Railway tracks are banked on curves
On a cold day when a room temperature is 15oC, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15oC, because
Sound produced at a point is heard by a person after 5 second, while the same sound is heard by another person after 6 seconds. If the speed of sound is 300 m/s, what could be the maximum and minimum distances between the two persons?
Intensity of sound at a point is ____ its distance from the source.
Of the four locations mentioned below the highest inside temperature will be attained in the pressure cooker operated with the pressure valve open
Rain is falling vertically downwards. To a man running east-wards, the rain will appear to be coming from