The completely dark portion of a shadow of an object is known as

A. umbra

B. penumbra

C. image

D. black portion of light

Please do not use chat terms. Example: avoid using "grt" instead of "great".

You can do it
  1. Tap water is placed in an open pad and allowed to evaporate. After some time the temperature of water
  2. When a body is immersed in a fluid the force of buoyancy of the fluid on the body depends on
  3. Which of the following sets of elementary particles have nearly equal masses?
  4. A proton is
  5. Solids have definite shapes. This is because
  6. The force that keeps a body in a circular motion la called
  7. The shadow below a tree has bright spots in it because
  8. Chronometer la an instrument to measure
  9. Where does the centre of gravity of a rubber ring lie?
  10. When an electric apparatus is fitted with a three core flexible lead the insulation on the three wires…
  11. The mode of travel of heat energy from the sun across the empty space beyond the earth's atmosphere…
  12. The speed at which light travels in vacuum is
  13. The device that is used to measure the electromotive force of a cell is
  14. A lightning conductor installed in a building
  15. When the resistance of a circuit increases the current will
  16. Echoes are produced by
  17. The device used to record the sound is
  18. In experiments on static electricity the standard method for obtaining small amounts of positive electricity…
  19. X-rays are used
  20. The Milky Way is
  21. The Cact that the compass needle does not point true north was observed first by
  22. When the disturbed electrons of an exited atom transfer back into lower energy levels they emit energy…
  23. The mixing up of two gases as a result of random motion of molecules is called
  24. Pyrometers are instruments used
  25. The unit of power in SI is
  26. A spherical mirror is
  27. A projectile is fired at an angle with the horizontal with a small velocity. Its horizontal range will…
  28. Drinks kept in a vacuum flask remain hot or cold as the case may be for a long time because
  29. In the visible spectrum which colour has the shortest wavelength?
  30. Sound travels fastest in