Miscellaneous — 5 Physics PYQs with Answers | UKPSC PYQ Hub

Question 1

The half-life of a radioactive substance is decay3/4th months. How much time it will take to of substance?

Accepted Answer

8 months. Given, Half-life T = 4 month N 1 (3/4)th (1/4)th = (since, has decayed, only remains) N 4 We know that - t/T 1 N=N   02 t/4 N 1 =  N 2 t/4 1 1 =  4 2 2 t/4 1 1 =    2 2 On comparing both sides we get- t =2 t = 8 month th 3 Therefore, it will take 8 months for of the substance to   4 decay.

Question 2

OMR stands for

Accepted Answer

Optical Mark Reader. OMR stands for Optical Mark Recognition or Optical mark reader.

Question 3

What portion of an iceberg floating in the ocean remains above the sea surface?

Accepted Answer

1/10. 1/10 portion of iceberg is above sea surface and 9/10 portion of iceberg is below the sea surface.

Question 4

The estimation of the age of earth is one by which of the following?

Accepted Answer

Uranium Dating. Radioactive uranium dating allows us to Estimate the age of earth. 4 116. As per Einsteins theory, energy equivalent of 1 gm (One gram) substance will be: (a) 5.6 × MeV (b) 9.09 × 1013 MeV (c) 5.6 × MeV (d) 5.6 × MeV

Question 5

Which of the following is more viscous lubricating oil?

Accepted Answer

SAE 70. In the SAE (Society of Automotive Engineers) grading system, higher numbers indicate greater viscosity. Therefore, SAE 70 oil has the highest viscosity.