Question

6. Which type of instrument would best be used to look at a grain of wheat pollen.

a) optical microscope

b) radio telescope

c) transmission electron microscope

d) scanning electron microscope

e) variable electron microscope

14) Rutherford’s alpha particle -scattering experiment showed that most alpha particles directed toward a thin metallic foil passed through with only slight deviations. From this evidence we can conclude that.....

18. Two stars star A and star B are the same size. The temperature of star A is 8000 K and the temperature of star B is 4000 K. How do their total luminosities compare.

Answer 1

6- The instrument which best suits to for wheat grain will be scanning electron microscope as it scans the surface of sample through focused beam of electrons and this interaction of electrons with atoms helps to find out various information about subtance like topoly,formation etc.

Hence option (d) is correct as scanning electron microscope will help to have detailed study of wheat grain.

7-Rutherfold alpha particle experiment shows that some particles were deflected by small angles hence showing that there is positive charge inside atom which is very dense and occupies small portion.

8- Luminousity is proportional to both temperature and radius of star hence

L is proportional to R²T⁴

Let luminosity of star A be L₁ and  Star B be L₂

Then we have size are same hence radius will be same

L₁/L₂= (R²×8000⁴)/(R²×4000⁴)

L₁/L₂=16

Hence luminosity of star A is 16 times the luminosity of star B

please do give a like