NEET 2017 | Atoms and Nuclei Question 33 | Physics

Radioactive material 'A' has decay constant '8 $$\lambda $$' and material 'B' has decay constant '$$\lambda $$'. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that 'A' will be e ?

$${1 \over {7\lambda }}$$

$${1 \over {8\lambda }}$$

$${1 \over {9\lambda }}$$

$${1 \over {\lambda }}$$

NEET 2017

MCQ (Single Correct Answer)

-1

The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is

0.5

NEET 2016 Phase 2

MCQ (Single Correct Answer)

-1

Out of Syllabus

The half-life of a radioactive substance is 30 minutes. The time (in minutes) taken between 40% decay and 85% decay of the same radioactive substance is

NEET 2016 Phase 2

MCQ (Single Correct Answer)

-1

If an electron in a hydrogen atom jumps from the 3^rd orbit to the 2^nd orbit, it emits a photon of wavelength $$\lambda $$. When it jumps from the 4^th orbit to the 3^rd orbit, the corresponding wavelength of the photon will be

$${{16} \over {25}}\lambda $$

$${9 \over {16}}\lambda $$

$${{20} \over 7}\lambda $$

$${{20} \over {13}}\lambda $$

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Biology

Zoology

Human Health and Diseases Body Fluids and Its Circulation Locomotion and Movement Neural Control and Coordination Reproduction in Organisms Reproductive Health Structural Organisation in Animals Digestion and Absorption Excretory Products and Their Elimination Chemical Coordination and Integration Human Reproduction Animal Kingdom Breathing and Exchange of Gases Evolution