Class XI Physics Important Questions on Units and Dimensions

A physical quantity P is described by the relation . If the relative errors in the measurement of a, b, c, and d respectively , then the relative error in the P will be:

Read the following statements
(i) 12300 has only 3 significant digits
(ii) 1.2300 × 10⁴ has only 5 significant digits
(iii) 0.012300 × 10⁶ has only 3 significant digits
(iv) all trailing zeroes are non significant digits
Correct statements are

A student measures the time period of 100 oscillations of a simple pendulum four times. The data set is 90s, 91s, 95 s and 92 s. If The minimum division in the measuring clock is 1s, then the reported mean time should be :

Two full turns of the circular scale of a screw gauge cover a distance of 1 mm on its main scale. The total number of divisions on the circular scale is 50. Further, it is found that the screw gauge has a zero error of -0.03 mm. While measuring the diameter of a thin wire, a student notes the main scale reading of 3 mm and the number of circular scale divisions in line with the main scale as 35. The diameter of the wire is

A, B, C, and D are four different physical quantities having different dimensions. None of them is dimensionless. But we know that the equation AD = C log_e(BD) holds true. Then which of the combination is not a meaningful quantity?