Question

1. A sample of germanium shows no Hall effect. If the mobility of electrons in germanium is 3500 cm cube/v. see and that of holes is 1400cm cube/v. see. What fraction of the current in the sample is carried by the electrons?

Answer 1

From the data given below calculate the value of first and third quartiles, second and ninth deciles and forty-fifth and fifty-seventh percentiles.
&
Height in
centimeters Number of
students Cumulative
frequency
161-167 79 79
167-173 92 171
173-179 60 231
179-185 22 253
185-191 5 258
191-197 2 260
Total 260


Since there are 260 total, the 1st quartile is at 260/4 = 65,
the 3rd quartiile is 3*65 = 195,
the 2nd decile is at 3*21 = 63,
the 9th decile is at 9*21 = 189,
the 45th percentile is at 45*210/100 = 94.5,
and the 57th percentile is at 57*210/100 = 119.7.

Using the last column, 65 is less than 79, so it is 161-167;
195 is greater than 171, but less than 231, so it is 173-179;
63 is less than 79, so it is 161-167,
189 is greater than 171, but less than 231, so it is 173-179;
94.5 is greater than 79, but less than 171, so it is 167-173; and
119.7 greater than 79 but less than 171, so it is is 167-173.