Question

Q2.Fill in the blanks

(i) The speed of light in air is _______.


(ii) White Light is _______ of colours.


(iii) The melting point of pure ice is ______ Kelvin.


(iv) _______ is the faster mode of transfer of heat.


(v) Convention cannot take place in _______.


(vi) The sound is a _______ wave.


(vii) The persistence of hearing is _______.


(viii) Each source of sound is a ________ body.


(ix) A _______ is a source of electricity.


(x) The flow of current in a wire is called _______.​

Answer 1

Answer:

about 300 million meters per second

Light always travels at the same speed across space. That speed, represented by the letter c, is about 300 million meters per second.

White light is a combination of all colors in the color spectrum. It has all the colors of the rainbow. Combining primary colors of light like red, blue, and green creates secondary colors: yellow, cyan, and magenta.

273 K.

Radiation

Convection is a transfer of heat energy through the movement of fluid particles. Hence, convection cannot take place in solids, since the solid particles are not fluid. Thus, convection only takes place in liquids and gases.

longitudinal waves

The sensation of hearing of any sound is called persistence of hearing .

Persistence of hearing of a human ear means how much time the sensation of any sound stay in our brain. For normal human ear the value is 0.1 s. Now If the persistence of hearing is increased or decreased compared to normalear ,it indicates the hearing loss of the human ear

Sound is produced when a body vibrates. In other words, each source of sound is a vibrating body.

The three major categories of energy for electricity generation are fossil fuels (coal, natural gas, and petroleum), nuclear energy, and renewable energy sources. Most electricity is generated with steam turbines using fossil fuels, nuclear, biomass, geothermal, and solar thermal energy.

Electric Current is the flow of electrons through a wire or solution. In a solid the electrons are passed from one positively charged metallic atom to next but in solution the electron is carried by the ions present in the solution. A solution capable of carrying charge is called an electrolyte.