Question 4871:

A girl of mass \(65 kg\) falls horn a bridge that \(50 m\) above the water. Calculate her kinetic energy after falling foings sees.

A. \(1125 J\)
B. \(28125 J\)
C. \(9375 J\)
D. 812501

Question 4872:

Which of the following is a mechanical wave?

A. Micro wave
B. Water wave
C. \()\)-ray
D. Infra-red ray

Question 4873:

The half-life of the radioactive substance of mass \(100 g\) is 30 minutes. What fractiods of the onginal mass is left over after \(3 hrs\) ?

A. \(3.125\)
B. \(6.25\)
C. \(1.5625\)
D. \(0.02563\)

Question 4874:

Two resistors \(12 \Omega\) and \(8 \Omega\) are connected in parallel, if the power developecin \(12 \%\), resistor is \(6 w\), determine the power developed in \(3.32\) resistor.

A. \(9 w\)
B. \(12 w\)
C. \(16 w\)
D. \(24 w\)

Question 4875:

How long will a 60 wart element take to heat water of mass \(9.5 kg\) at \(20^{\circ} C\) to \(90^{\circ} C\). Neglect heat loss (S.H. C. of water \(=4200 jkg ^{-1} K ^{-1}\) )

A. 350 secs
B. 1260 secs
C. \(2100 secs\)
D. 1500 secs