Question 186: Semiconductors and Logic Gates

Question

If the ratio of the concentration of electrons to that of holes in a semiconductor is $${7 \over 5}$$ and the ratio of currents is $${7 \over 4},$$ then what is the ratio of their drift velocities?

Accepted Answer

$${{{I_e}} \over {{I_h}}} = {{n{}_eeA{v_e}} \over {n{}_heA{v_h}}}$$
$$ \Rightarrow {7 \over 4} = {7 \over 5} 	imes {{{v_e}} \over {{v_h}}}$$
$$ \Rightarrow {{{v_e}} \over {{v_h}}} = {5 \over 4}$$

Answer

$${5 \over 8}$$

Answer

$${4 \over 5}$$

Answer

$${5 \over 4}$$

Answer

$${4 \over 7}$$

Semiconductors and Logic Gates

If the ratio of the concentration of electrons to that of holes in a semiconductor is ${7 \over 5} and the ratio of currents is {7 \over 4},$ then what is the ratio of their drift velocities?

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