1
JEE Main 2020 (Online) 4th September Morning Slot
Numerical
+4
-0
In a compound microscope, the magnified virtual image is formed at a distance of 25 cm from the eye-piece. The focal length of its objective lens is 1 cm. If the magnification is 100 and the tube length of the microscope is 20 cm, then the focal length of the eye-piece lens (in cm) is __________.
2
JEE Main 2020 (Online) 3rd September Evening Slot
Numerical
+4
-0
When an object is kept at a distance of 30 cm from a concave mirror, the image is formed at a distance of 10 cm from the mirror. If the object is moved with a speed of 9 cms–1, the speed (in cms–1) with which image moves at that instant is ____.
3
JEE Main 2020 (Online) 3rd September Morning Slot
Numerical
+4
-0
An observer can see through a small hole on the side of a jar (radius 15 cm) at a point at height of 15 cm from the bottom (see figure). The hole is at a height of 45 cm. When the jar is filled with a liquid up to a height of 30 cm the same observer can see the edge at the bottom of the jar. If the refractive index of the liquid is N/100, where N is an integer, the value of N is _____.
4
JEE Main 2020 (Online) 2nd September Evening Slot
Numerical
+4
-0
A light ray enters a solid glass sphere of refractive index $$\mu$$ = $$\sqrt 3$$ at an angle of incidence 60o. The ray is both reflected and refracted at the farther surface of the sphere. The angle (in degrees) between the reflected and refracted rays at this surface is ________.