A radioactive isotope has a decay constant of 10-6s-1.
Calculate its half - life?
5.93 x 106s
6.93 x 105s
6.93 x 109s
5.93 x 107s
Correct answer is B
t1/2 = \(\frac{0.693}{\gamma}\) = \(\frac{0.693}{10^-6}\)
= 6.93 x 105
Which of the following electromagnetic waves has the shortest wavelength?
Visible Light
Ultraviolet rays
Infrared rays
Gamma rays
Correct answer is D
No explanation has been provided for this answer.
40s
10s
20s
5s
Correct answer is B
t = \(\frac{v - u}{a}\) = \(\frac{20 - 0}{2}\)
= 10s
30s
20s
25s
15s
Correct answer is D
The total time of flight is given as
\(T = \frac{2usin\theta}{g}\)
Hence, time to maximum height is half of the total time of flight,
t = \(\frac{u sin\theta}{g}\)
= \(\frac{300 \text {sin} 30}{10}\) = 15s
30cm
10cm
20cm
25m
Correct answer is C
Clockwise moment = Anti-clockwise moment
10 x 30 = 15 x X
X = 20cm