A count rate meter shows a count of 240 per minute from a given radioa – McqOptions

MCQOPTIONS

1.	A count rate meter shows a count of 240 per minute from a given radioactive source. One hour later the meter shows a count rate of 30 per minute. The half-life of the source is [KCET 2004]
A.	120 min
B.	80 min
C.	30 min
D.	20 min
Answer» E.

Discussion

No Comment Found

Related MCQs

Find the equivalent thermal resistance of combination of rods as shown in figure. Every rod has same length I and cross-sectional area A. Thermal conductivities are mentioned in figure.
The ripple factor in a half wave rectifier is [RPMT 2002]
Assertion : Two persons on the surface of moon cannot talk to each other. Reason : There is no atmosphere on moon.
A potential barrier of 0.50 V exists across a P-N junction. If the depletion region is \[5.0\times {{10}^{-7}}\]m wide, the intensity of the electric field in this region is [UPSEAT 2002]
The laptop PC?s modern electronic watches and calculators use the following for display
The reason of current flow in P-N junction in forward bias is [RPMT 2000]
The period of a simple pendulum is doubled, when [CPMT 1974; MNR 1980; AFMC 1995; Pb. PET/PMT 2002]
The period of oscillation of a simple pendulum of constant length at earth surface is T. Its period inside a mine is [CPMT 1973; DPMT 2001]
Assertion : To protect any instrument from external magnetic field, it is put inside an iron body. Reason : Iron is a magnetic substance.
Two travelling waves \[{{y}_{1}}=A\sin [k(x-ct)]\] and\[{{y}_{2}}=A\sin [k(x+ct)]\]are superimposed on string. The distance between adjacent nodes is