Which one of the following statements is not true about cosmic rays?
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
A count rate meter shows a count of 240 per minute from a given radioactive source. One hour later the meter shows a count rate of 30 per minute. The half-life of the source is _______.
If a projectile is launched at 450 with velocity lOOm/s, it hit the target. It will have double the range if its velocity is:
A beam of light of wavelength 600 nm from a distant source falls on a single slit 1mm wide and the resulting diffraction pattern is observed on a screen 2m away. The distance between the first dark fringes on either side of the central bright fringe is _______.
Minimum number of unequal vectors which can give zero resultant are
If the change in the value of g at the height h above the surface of the earth is the same as at a depth x below it, then (both x and h being much smaller than the radius of the earth)
A plane mirror is approaching you at a speed of 10 cm/s you can see your image in it. At what speed will your image approach you?
The maximum number of possible interference maxima when slit separation is equal to 4 times the wavelength of light used in a double slit experiment is
Electronic motors operating at low voltages tend to burn out because
lf a black body emits 0.5 joules of energy per second when it is at 27°C , then the amount of energy emitted by it when it is at 627°C will be
The absorption of ink by blotting paper involves
Lognitudinal waves and Transverse waves are types of ?
Which of the following are true about speed of sound?
(i) Sound propagates through a medium at a finite speed.
(ii) The speed of sound decreases when we go from solid to gaseous state.
(iii) Speed of sound increases with increase in temp.
A thief stole a box with valuable article of weight ‘W’ and jumped down a wall of height h. Before he reach the ground he experienced a load o
The ratio of minimum wavelengths of Lyman and Balmer series will be
Three liquids of equal masses are taken in three identical cubical vessels A, B and C. Their densities are PA, PB and PC respectively. But PA < PB < PC. The force exerted by the liquid on the base of the cubical vessel is ______
The power dissipated in a resistance is given by?
The incident ray, reflected ray and normal to the reflecting surface at the incident point all never lie in same plane.
Who discovered Diode Bulb ?
Siphon will fail to work if
Which law states, "The rate of loss of heat by a body is directly proportional to the difference in temperature between the body and the surroundings."
Read the following statements carefully Y: The resistivity of a semiconductor decreases with increase of temperature Z : In a conducting solid, rate of collisions between free electrons and ions increases with increases of temperature Select the correct statements (s) from the following
Two beams of red and violet colours are made to pass separately through a prism of A = 60°. In the minimum deviation position, the angle of refraction inside the prism will be
The SI unit of resistance is?
The earth’s gravity acts on both the spacecraft and the bodies in it, giving each?