Short Answer TypeIf the diameter of a carbon atom is 0.15 nm, calculate the number of carbon atoms which can be placed side by side in a straight line across length of scale of length 20 cm long.
Long Answer TypeShort Answer TypeA certain particle carries 2.5 X 10-16C of static electric charge. Calculate the number of electrons present in it.
In Milikan's experiment, static electric charge on the oil drops has been obtained by shining X-rays. If the static electric charge on the oil drop is - 1.282 X 10-18C, calculate the number of electrons present on it.
Long Answer TypeFind: (a) the total number and (b) the total mass of protons in 34 mg of NH3 at STP.
Will the answer change if the temperature and pressure are changed ?
Light is an important form of energy, According to Newton's corpuscular theory,the light was considered as a stream of particles called corpuscles of light. This theory could explain the phenomenon of reflection and refraction, but failed to explain the phenomenon of diffraction and interference. Therefore, the corpuscular theory was discarded and replaced by the wave theory of light. According to this theory, light is transmitted in the form of electromagnetic waves. These waves are associated with the oscillating electric field and magnetic fields.
The energy emitted from any source in the form of radiation is called radiant energy. The most common forms of radiant energy are cosmic rays, gamma rays, X-rays, ultraviolet rays, visible rays, infrared rays, radio waves and heat. Clark Maxwell (1856) proposed that radiant energy has wave character. These waves are associated with both electric and magnetic fields, thus, these radiations are called electromagnetic radiations. All types of electromagnetic radiations travel through space with the same velocity i.e. the velocity of light (3 x 108 ms-1).
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