The device used for measuring the wavelength of X-rays is

• cyclotron

• bragg spectrometer

• mass spectrometer

• GM counter

Ultraviolet rays can be used in water treatment as

• precipitator

• hydrolyser

• disinfectant

• flocculator

Which one of the following is responsible for the working of Newton's color disc experiment?

• Formation of pure spectra

• Formation of impure spectra

• Persistence of vision

• Principle of complementary colour

The dimension MLT^-2 corresponds to

• force

• work done

• acceleration

• veolcity

Who is the founder of quantum theory of radiation?

• Einstein

• Bohr

• Plank

• S N Bose

Fiber optics cable used in communication, works on the principle of

• regular reflection of light

• diffuse reflection of light

• refraction of light

• total internal reflection of light

Rutherford's scattering experiment proved the presence of

• atoms in all matter

• electrons in atoms

• neutrons in atoms

• nucleus in atoms

The apparent weight of a man in a lift is less than the real weight, when

• the lift is going up with uniform speed

• the lift is going down with an acceleration

• the lift is going down with uniform speed

• the lift is going up with an acceleration

89.

A particle moving with uniform speed

• must have uniform velocity

• cannot have uniform velocity

• may have uniform velocity

• will have no velocity

Device which uses sound waves for detection and ranging is called

• radar

• sonar

• pukar

• None of these