Answer the following question: Optical and radio telescopes are built on the ground but X-ray astronomy is possible only from satellites orbiting the earth. Why?

Answer the following question: Long distance radio broadcasts use short-wave bands. Why?

Answer the following question: It is necessary to use satellites for long distance TV transmission. Why?

Answer the following questions: When a tiny circular obstacle is placed in the path of light from a distant source, a bright spot is seen at the centre of the shadow of the obstacle. Explain why?

Answer the following questions: A low voltage supply from which one needs high currents must have very low internal resistance. Why?

Answer the following questions regarding earth’s magnetism:Geologists claim that besides the main magnetic N-S poles, there are several local poles on the earth’s surface oriented In different directions. How Is such a thing possible at all?

Answer the following questions: Ray optics is based on the assumption that light travels in a straight line. Diffraction effects (observed when light propagates through small apertures/slits or around small obstacles) disprove this assumption. Yet the ray optics assumption is so commonly used in understanding location and several other properties of images in optical instruments. What is the justification?

Answer the following questions: When viewing through a compound microscope, our eyes should be positioned not on the eyepiece but a short distance away from it for best viewing. Why? How much should be that short distance between the eye and eyepiece?