Numerical problems

Problem 1

 If 2 coulomb of charge flows through a circuit for 10 seconds, calculate the current.

Solution

Charge (Q) = 2 C; Time (t) = 10 s

I = Q/t = 2/10 = 0.2 A

Problem 2

Convert 60° into radian.

Solution

We know that,

1° = π/180

60° = π/180 × 60 = π/3 radian

Problem 3

Convert 4π into degrees.

Solution

We know that,

π radian = 180°

π/4 radian = 180/4 = 45°

Problem 4

Round off the number 1. 864 to two decimal places.

Solution

We need to round off the number to two decimal places. So, the last digit to be kept is 6. Since the next digit is less than 5, we can retain 6 as it is. So the answer is 1. 86.

Problem 5

Round off the number 1. 868 to two decimal places.

Solution

We need to round off the number to two decimal places. So, the last digit to be kept is 6. Since the next digit is more than 5, we should increase the second digit by one. So, the answer is 1. 87.