You have three lenses L 1 , L 2 and L 3 of power +10 D , + 5 D and -10 D respectively. State the nature and focal length of each lens. Explain which of the three lens will form a Virtual and magnified image of an object placed at 15 cm from the lens.

Which of the following statements are true for an isothermal process? check all that apply. - during an isothermal process, the work done by the gas equals the heat added to the gas. - during an isothermal process, the internal energy of the system changes. - an isothermal process is carried out at constant temperature. - an isothermal process is carried out at constant pressure. - an isothermal process is carried out at constant volume.