Question
Explain in brief about emission spectrum and absorption spectrum.
✓
Answer
• Emission Spectrum
→Each element has a characteristic spectrum of radiation emitted by it.
→When an atomic gas or vapour is excited at low pressure by passing an electric current through it, the emitted radiation has a spectrum which contains certain specific wavelengths.
→A spectrum of this type is called emission line spectrum and it consists of bright lines on a dark background.
→The spectrum emitted by atomic hydrogen is shown in the figure.
• Absorption spectrum :
→When white light is passed through an atomic gas, certain types of wavelengths are absorbed.
→An atom absorbs only those wavelengths that takes it from one excited state to another excited state.
→As a result if the emitted light is analyzed with a spectrometer, a dark line is seen instead of the wavelength that has been absorbed.
→Thus, this is called the absorption spectrum of the material of the gas.
→Each element has a characteristic spectrum of radiation emitted by it.
→When an atomic gas or vapour is excited at low pressure by passing an electric current through it, the emitted radiation has a spectrum which contains certain specific wavelengths.
→A spectrum of this type is called emission line spectrum and it consists of bright lines on a dark background.
→The spectrum emitted by atomic hydrogen is shown in the figure.
• Absorption spectrum :
→When white light is passed through an atomic gas, certain types of wavelengths are absorbed.
→An atom absorbs only those wavelengths that takes it from one excited state to another excited state.
→As a result if the emitted light is analyzed with a spectrometer, a dark line is seen instead of the wavelength that has been absorbed.
→Thus, this is called the absorption spectrum of the material of the gas.
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
A conducting circular loop of radius a is connected to two Iong, straight wires. The straight wires carry current I as shown in figure. Find the magnetic field B at the centre of the loop.
Find the average magnitude of linear momentum of a helium molecule in a sample of helium gas at 0°C. Mass of a helium molecule $= 6.64 \times 10^{-27}kg$ nd Boltzmann constant $= 1.38 \times 10^{-23}JK^{-1}.$
→A copper wire bent in the shape of a semicircle of radius r translates in its plane with a constant velocity v. A uniform magnetic field B exists in the direction perpendicular to the plane of the wire. Find the emf induced between the ends of the wire if:
- The velocity is perpendicular to the diameter joining free ends.
- The velocity is parallel to this diameter.
There is no change in the energy of a moving charged particle in a plane magnetic field. Explain, why?
What is conductivity ? On which what factors does it depend and also write its unit and dimension.
Consider a circuit containing an ideal battery connected to a resistor. Do "work done by the battery" and "the thermal energy developed" represent two names of the same physical quantity?
What are the readings of the ammeters $A_1$ and $A_2$ shown in figure. Neglect the resistance of the meters.
→Plot a graph showing the variation of stopping potential with the frequency of incident radiation for two different photosensitive materials having work functions $W_1$ and $W_2\left(W_1>W_2\right)$. On what factors does the (i) slope and (ii) intercept of the lines depend?
→A proton and an a-particle have the same de-Broglie wavelength. Determine the ratio of (i) Their accelerating potentials and (ii) Their speeds.
State the types of electric charge. Who coined these names?