1
JEE Main 2016 (Online) 9th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A hydrogen atom makes a transition from n = 2 to n = 1 and emits a photon. This photon strikes a doubly ionized lithium atom (z = 3) in excited state and completely removes the orbiting electron. The least quantum number for the excited state of the ion for the process is :
A
2
B
3
C
4
D
5
2
JEE Main 2016 (Offline)
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
Half-lives of two radioactive elements $$A$$ and $$B$$ are $$20$$ minutes and $$40$$ minutes, respectively. Initially, the samples have equal number of nuclei. After $$80$$ minutes, the ratio of decayed number of $$A$$ and $$B$$ nuclei will be:
A
$$1:4$$
B
$$5:4$$
C
$$1:16$$
D
$$4:1$$
3
JEE Main 2015 (Offline)
MCQ (Single Correct Answer)
+4
-1
Change Language
As an electron makes a transition from an excited state to the ground state of a hydrogen - like atom/ion :
A
kinetic energy decreases, potential energy increases but total energy remains same
B
kinetic energy and total energy decrease but potential energy increases
C
its kinetic energy increases but potential energy and total energy decrease
D
kinetic energy, potential energy and total energy decrease
4
JEE Main 2014 (Offline)
MCQ (Single Correct Answer)
+4
-1
Hydrogen $$\left( {{}_1{H^1}} \right)$$, Deuterium $$\left( {{}_1{H^2}} \right)$$, singly ionised Helium $${\left( {{}_2H{e^4}} \right)^ + }$$ and doubly ionised lithium $${\left( {{}_3L{i^6}} \right)^{ + + }}$$ all have one electron around the nucleus. Consider an electron transition from $$n=2$$ to $$n=1.$$ If the wavelengths of emitted radiation are $${\lambda _1},{\lambda _2},{\lambda _3}$$ and $${\lambda _4}$$ respectively then approximately which one of the following is correct?
A
$$4{\lambda _1} = 2{\lambda _2} = 2{\lambda _3} = {\lambda _4}$$
B
$${\lambda _1} = 2{\lambda _2} = 2{\lambda _3} = {\lambda _4}$$
C
$${\lambda _1} = {\lambda _2} = 4{\lambda _3} = 9{\lambda _4}$$
D
$${\lambda _1} = 2{\lambda _2} = 3{\lambda _3} = 4{\lambda _4}$$
JEE Main Subjects
EXAM MAP
Medical
NEET
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
CBSE
Class 12