A radioactive substance has a half life of 20 days. What ...
A radioactive substance has a half life of 20 days. What fraction of the original radioactive nuclei will remain after 80 days?
\( \frac{1}{32} \)
\( \frac{1}{16} \)
\( \frac{1}{8} \)
\( \frac{1}{4} \)
Correct answer is B
80 days = 4 half lives (i.e 4 x 20dqs = 80dq)
But the fraction always left by any radioactive material after 4 half lives is
\( \left ( \frac{1}{2} \right)^4 = \frac{1}{16} \)
The diagram above illustrates a mode of vibration of a wire of length 125 cm. The speed of the ...
The images formed by a diverging lens are always ...
Calculate the inductive reactance of the circuit shown above. ...
What is the value of R when G shows no deflection in the circuit illustrated above? ...
Arrange the following radiations in order of increasing ionization of air. I. Alpha Il. Gamma IIl...