You have three lenses L1, L2 and L3 of powers +10D, +5D and -10D respectively. *IMPORTANT* a. State the nature and focal length of each lens.

b. Explain which of the three lenses will form a virtual and magnified image of an object

placed at 15 cm from the lens.

c. Draw the ray diagram in support of your answer.

Explain vector addition, triangle method and parallelogram method

(**i would really appreciate if this was answered soon** ) which pair of quantities includes one quantity that increases as the other decreases during simple harmonic motion?

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?