Energy Band Theory and Electrical Properties of Matter

Elemental semiconductor cannot be used to make visible LEDs.

What are elemental semiconductors?

Valence band is-

Valence band having low energy state.

Describe the theory of valence band?

Insulator are important to keep us safe from _____.

Plastic, rubber, paper, glass and dry air are the example of insulators?

What are insulators?

Conductivity is an object's ability to transmit current.

The reverse of conductivity is-

What is the SI unit of conductivity for an object?

Write a distinguishing features between conductors, semiconductors and insulators on the basis of energy gap and Conductivity.

Which of the following arrangements is correct on the basis of conductivity of materials?

What is Conduction band?

The conduction band and valence band in semiconductors are separated by energy gap of-

In a semiconductor at room temperature, conduction band is partially filled.

The conduction band is completely empty in _____.

The energy band gap of gallium arsenide phosphate is $1.98 e\mathrm{V}$. Calculate the wavelength of electromagnetic radiation emitted (in Angstrom), when electrons and holes combine in this alloy semiconductor directly. (Take Planck's constant $\left(h\right)=6.62\times {10}^{-34 }\mathrm{J} \mathrm{s}$)

The forbidden gap in the energy bands of germanium at room temperature is about 

If the energy of a photon of sodium light $(\mathrm{\lambda }=589 \mathrm{n}\mathrm{m})$ is equal to the bandgap of a semiconductor, calculate the minimum energy required to create hole-electron pair. Take, $h=6.6\times {10}^{-34} \mathrm{J} \mathrm{s}, c=3\times {10}^8 \mathrm{m} {\mathrm{s}}^{-1}$.