Question

1). A student obtained a sharp image of the grills of a window on his screen using a concave mirror. His teacher remarked that for getting better results, a well lit distant object (preferably the sun) should be focused on the screen. What should be done for this purpose?A) Move the screen slightly away from the mirrorB) Move the mirror slightly towards the screenC) Move the screen and the mirror away from the objectD) Move the screen and the mirror towards the object

2). Which of the following lenses would you prefer to use while reading small letters in a booka) A convex lens of focal length 50 cmb) A concave lens of focal length 50 cmc) A convex lens of focal length 5 cmd) A concave lens of focal length 5 cm

3)Permanent hardness of water is due to the presence of :a) hydrogencarbonates of calcium and magnesiumb) chloridesand sulphates of calcium and magnesiumc) hydrogencarbonates and sulphates of calcium and magnesiumd) chlorides and carbonates of calcium and magnesium

4)40. Blue colour of the sky and twinkling of stars are due toa) Reflection and Atmospheric refraction of sunlight.b) Scattering and Atmospheric refraction of sunlight.c) Dispersion and scattering of sunlight.d) Atmospheric refraction and scattering of sunlight.

5)Variation is beneficial to the species but not necessarily for the individual. Give three reasons to support it.

Answer 1

After about a week the seeds began to sprout and grow into a tree with these ... (Papaya - 03a) At the very top of the papaya tree trunk, we can see the new leaves  ...