Because the refractive indexes of the immersion oil and the glass microscope slide are the same; the oil prevents the refraction of the incoming light rays.
An invisible space is present between the slide and the lens that contains air.
When the light rays fall on the slide and lens they might get refracted due to air present between them.
If the rays get refracted then the diameter of the objective lens will expand further.
So in order to prevent the refraction of light, it is very important to lubricate the surface of the lens because without oil the light rays refract from their original path.
If you need to learn more about the refractive index click here
brainly.com/question/5170843
#SPJ4
Answer:
541.14 m/s
Explanation:
We are given that
Mass of cannon=
Mass of shell,
Initial velocity of shell,v=547 m/s
We have to find the velocity of shell fired from this loose cannon.
According to law of conservation of momentum

Initial momentum of system=0


When the cannon is bolted to the ground then only shell moves and kinetic energy of system equals to kinetic energy of shell
Kinetic energy of shell,
K.E of shell=
K.E of shell=
K.E of shell=
2K.E of shell=
Velocity of shell fired from this loose cannon,v_2=


Hence, the velocity of shell fired from this loose cannon would be 541.14 m/s