MCQ
Biological importance of Ozone layer is
- ✓It stops ultraviolet rays
- BOzone rays reduce green house effect
- COzone layer reflects radio waves
- DOzone layer controls $\mathrm{O}_2 / \mathrm{H}_2$ radio in atmosphere
✓
Answer
Correct option: A.
It stops ultraviolet rays
(a) It stops ultraviolet rays
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
According to de-Broglie, the de-Broglie wavelength for electron in an orbit of hydrogen atom is $10^{-9} \,m.$ The principle quantum number for this electron is
→Assertion : The earth’s magnetic field is due to iron present in its core.
Reason : At a high temperature magnet losses its magnetic property or magnetism.
Reason : At a high temperature magnet losses its magnetic property or magnetism.
When Ge crystals are doped with phosphorus atom, then it becomes
An N-type and P-type silicon can be obtained by doping pure silicon with
The electron density of $E, F_1, F_2$ layers of ionosphere is $2 \times 10^{11}$, $5 \times 10^{11}$ and $8 \times 10^{11}\, m^{-3}$ respectively. What is the ratio of critical frequency for reflection of radiowaves
→The barrier potential of a $p-n$ junction depends on
→$(1)$ type of semiconductor material
$(2)$ amount of doping
$(3)$ temperature
Which one of the following is correct?
An isosceles prism of angle $A=30^{\circ}$ has one of its surfaces silvered. Light rays falling at an angle of incidence $60^{\circ}$ on the other surface retrace their path after reflection from the silvered surface. The refractive index of prism material is
→Match List$-I$ with List$-II$
→| List$-I$ | List$-II$ |
| $(a)$ Phase difference between current and voltage in a purely resistive $AC$ circuit | $(i)$ $\frac{\pi}{2} ;$ current leads voltage |
| $(b)$ Phase difference between current and voltage in a pure inductive $AC$ circuit | $(ii)$ zero |
| $(c)$ Phase difference between current and voltage in a pure capacitive $AC$ circuit | $(iii)$ $\frac{\pi}{2} ;$ current lags voltage |
| $(d)$ Phase difference between current and voltage in an $LCR$ series circuit | $(iv)$ $\tan ^{-1}\left(\frac{X_{C}-X_{L}}{R}\right)$ |
Choose the most appropriate answer from the options given below:
In the shown circuit, what is the potential difference across $A$ and $B$ ......... $V$
→Decay constant of radium is λ. By a suitable process its compound radium bromide is obtained. The decay constant of radium bromide will be