Read the two statements carefully to mark the correct option out of the options given below:

Statement - 1 Dimensional constants are the quantities whose values are constant.
Statement - 2 Dimensional constants are dimensionless.

Statement - 1 is true, Statement - 2 is false.

The correct answer is Option (3) → Statement - 1 is true, Statement - 2 is false.

Let us analyze the statements:

Statement 1: Dimensional constants are the quantities whose values are constant.

Statement 2: Dimensional constants are dimensionless.

Statement 1 correctly defines dimensional constants as quantities whose values remain constant. These constants typically appear in equations involving physical quantities to maintain dimensional consistency. For example, in equations involving time, length, mass, etc., constants such as the gravitational constant (G) or the speed of light (c) are often used.

Statement 2 claims that dimensional constants are dimensionless, which is incorrect. Dimensional constants do have dimensions associated with them; otherwise, they would not be able to maintain dimensional consistency in equations. For instance, the gravitational constant (G) has dimensions of \([L^3 M^{-1} T^{-2}]\), and the speed of light (c) has dimensions of \([L T^{-1}]\). These dimensions are necessary to ensure that the units on both sides of an equation match.

Therefore, Statement 1 is true, but Statement 2 is false because dimensional constants do have dimensions.

So, the correct option is: Statement - 1 is true, Statement - 2 is false.