Physics

Q1. As a result of annihilation of electron and positron, number of γ–ray (Gama ray) photons are: ________?

Q2. Why Ballistic missile fails in some circumstances of precision ?

Q3. How many types of units are in SI ?

Q4. Concentration of red cells in blood is about______________?

Q5. Which is the fastest?

Q6. When a wheel 1 m in diameter makes 30 rev min the linear speed of the point on its rim in ms-1 is_______________?

Q7. Blood vessels are______________?

Q8. A moving coil galvanometer of resistance 100? gives half scale deflection for a current of 20mA. What will be the potential difference across it ?

Q9. An alpha particle can produce fluorescence in__________________?

Q10. A diffraction grating has 500 lines per mm. Its slit spacing or grating element will be equal to ____________________?