Reflection-HOTS Flashcards
light exhibits dual nature. substantiate
light exhibits dual nature that is both particle nature and wave nature. The particle nature lf light explains the phenomena of reflection and refraction when the size of the particle is greater than the wavelength of light. The wave nature of light explains the phenomena of diffraction and interference where the wavelength of light is greater than the size of the particle.
define reflectance
reflectance refers the ratio of the amount of light reflected from the surface to the amount of light falling on it. its expressed as a %
why does a polished shoe shine brightly
the shoe polish cleans the dust from the pores and provides a shiny surface which gives rise to regular reflection of light, whihc gives us a glared feeling
how can we read newspaper
the paper of newspaper consists of minute irregularities. thus it gives irregular reflection and the light is spread over a large area allowing us to read the newspaper.
what happens when a light ray strikes normally on a surface
light ray which falls normall, perpendicularly at 90 on a surface, retraces its path.
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an incident angle is 50 degress, find the total angle turned by the plane mirror
Since the angle of incidence is equal to the angle of reflection, the angle of incidence is also 50 degrees. The angle between the incident ray and reflected ray is the sum of the angle of incidence and the angle of reflection which is (50+50) degrees i.e. 100 degrees.
give the uses of plane mirror
-used in a periscope
-used in a galvanometer scale
-used in compass box
-used in vehicles,to see the turnings and speed of behind traffic
why is concave mirror called convergent mirror and convex called divergent
concave mirror is called converging mirror because it converges a parallel beam of light falling on it and the convex mirror is called diverging becausr it diverges a parallel beam of light fallling on it.
why is concave mirror used in vehicle headlights
concave mirrors are used in vehicle headlights, tourches and lights to produce intense parallel beam of light. the bulb is placed at the focus of the concave mirror or reflecting surface in the headlight. a beam of light from the bulb after relfection by the mirror moves as a parallel beam of light. the parallel beam of light illuminated the road ahead.
why is concave mirror used in shaving and makeup mirror
when an object is kept close to a concave mirror(ie between pole and focus), the image is virutal erect and nelarged, for this purpose, men use this in the mirror to see their face clearly. and women also use it to do makeup
why is concave mirror used in solar furnaces
when a parallel beam of sunlight falls on a concave mirror or concave reflecting surface, the light is focussed at the focus of the mirror. sunlight is considered as light from infinity. so the temperature of the object at the focus increases considerably,hence the water in the container is heated or boiled.
why is the concave mirror used in hospitals by ent
concave mirrors are used by dentists and ent specialists. when a concave mirror is close to an object an virutal erect and enlarged image is formed. so when the dentist or ent uses it, they can examine the earnoseteeththroag organs clealry.
why is convex mirror used in rear view mirror
it used because it forms a virtual, erect and diminished image of the behind traffic. since the imageformed by the mirror is small, the field of view is increased. so the driver can see a larger area of the behind traffic. this mirror is clled drivers mirror
why is convex mirror used in big shopping stores
convex mirror is used in shops to monitor the activities of the customers. since the ffield of view on a convex mirror is large, the mirror can monitor the activities of customers over a lrger area.
convex mirror is most advantegeous to use in a street light than plan mirror why
convex mirror diverges/spreads light over a larger area.
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