Explain Why `7times11times13times+13` and `7times6times5times4times3times2times1times+5` are composite number.

Explain why (7 times 11 times 13)+13 " and " (7 times 6 times 5 times 4 times 3 times 2 times 1)+5 are composite numbers.

Explain why 7xx11 xx 13 + 13 and 7 xx 6xx 5 xx 4 xx 3 xx 2xx 1 +5 are composite numbers.

Define relaxation time or mean free time.

A coin is tossed 2 n times. The chance that the number of times one gets head is not equal to the number of times one gets tail is

A two digit number is four times the sum of the digits. It is also equal to 3 times the product of digits. Find the number.

A two digit number is four times the sum of the digits. It is also equal to 3 times the product digits . Find the number.

The number densities of electrons and holes in an extrinsic semiconductor are 8 xx 10^13 cm^-3 and 5 xx 10^12cm^-3 respectively and their respective mobilities are : 23 xx 10^3cm^2//Vs and 10^2cm^2//Vs . The conductivity of the semiconductor is

The dimensions of a block are 1 cm xx 1 cm xx 100 cm . If specific resistance of its material is 3 xx 10^-7 ohm metre then the resistance between the opposite rectangular faces is :