Question

a pencil partially immersed in water appears to be bent name the phenomenon responsible for the observation and explain it

Answer 1

Refraction of light phenomenon takes place. When the light ray travels from one medium to another it appears bend . This same takes place in this experiment when the light ray travels from air to water it appears bend .

Answer 2

the phenomenon responsible for for it is the refraction of light
refraction of light=when a ray of light pass through or change it's medium from low to high medium it's changes it's direction or bent
as ray of light come from air to water and Chang it's medium the pencil appears to be bent.