MCQ
After five half lives what will be the fraction of initial substance
- A${\left( {\frac{1}{2}} \right)^{10}}$
- ✓${\left( {\frac{1}{2}} \right)^5}$
- C${\left( {\frac{1}{2}} \right)^4}$
- D${\left( {\frac{1}{2}} \right)^3}$
✓
Answer
Correct option: B.
${\left( {\frac{1}{2}} \right)^5}$
b
(b)$\frac{N}{{{N_0}}} = {\left( {\frac{1}{2}} \right)^n} = {\left( {\frac{1}{2}} \right)^5}$
(b)$\frac{N}{{{N_0}}} = {\left( {\frac{1}{2}} \right)^n} = {\left( {\frac{1}{2}} \right)^5}$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
As a part of a maintenance inspection the compressor of a jet engine is made to spin according to the graph as shown. The number of revolutions made by the compressor during the test is
Four ammeters with identical internal resistance $r$ and a resistor $R$ are connected to a current source as given. if reading of $A_1$ and $A_2$ is $3\ A$ and $5\ A$ respectively then the reading $A_4$ is ............. $A$
→A coil of inductance $0.20\, H$ is connected in series with a switch and a cell of $emf$ $1.6\, V$. The total resistance of the circuit is $4.0\, \Omega $. What is the initial rate of growth of the current when the switch is closed ?.......$A\, s^{-1}$
→The rotational kinetic energy of a solid sphere of mass $3 \;kg$ and radius $0.2\; m$ rolling down an inclined plane of height $7\; m$ is
→Two bodies of masses ${m_1}$ and ${m_2}$ have equal kinetic energies. If ${p_1}$ and ${p_2}$ are their respective momentum, then ratio ${p_1}:{p_2}$ is equal to
→The focal length of the obejctive lens and the eye piece of a microscope are $2\, cm$ and $5\, cm$ respectively and the distance between them is $20\, cm$. Find the distance of the object from objective lens when final image is seen by the eye is $25 \,cm$ from the eye piece......$cm$
→A $2\,kg$ chain is in the form of a heap. Its length is $2\,m$. Its one end is being pulled at constant speed of $2\,m/s$ horizontally. The power delivered to the chain is (in $W$).
→Photons of energy $7 \,eV$ are incident on two metals $A$ and $B$ with work functions $6 \,eV$ and $3 \,eV$, respectively. The minimum de-Broglie wavelengths of the emitted photoelectrons with maximum energies are $\lambda_A$ and $\lambda_B$ respectively, where $\lambda_A / \lambda_B$ is nearly
→Electric field at a place is $\overrightarrow {E\,} = {E_0}\hat i\,V/m$ . A particle of charge $+q_0$ moves from point $A$ to $B$ along a circular path find work done in this motion by electric field
→A galaxy is moving away from the earth at a speed of $286\, kms ^{-1}$. The shift in the wavelength of a red line at $630\, nm$ is $x \times 10^{-10}\, m$. The value of $x ,$ to the nearest integer, is........
→[Take the value of speed of light $c,$ as $3 \times 10^{8}$ $\left. ms ^{-1}\right]$