Full fledge assessment videos for light-reflection-and-refraction

Full fledge assessment (Please watch the above videos before attempting this assessment)

Question 1 of 20
Q1. A concave mirror is used in a solar cooker because 
  • it converges at the focus
  • it diverges
  • it scatters light rays in all directions
  • Both a and b

Solution :

A concave mirror is used in a solar cooker because it converges at the focus.
Still have doubt? Watch Video
Q2. A ____________ is used in a solar cooker. 
  • Concave mirror
  • Convex mirror
  • Concave lens
  • Convex lens

Solution :

A concave mirror is used in a solar cooker.
Still have doubt? Watch Video
Q3. A concave lens is ________ at the edges. 
  • steeper
  • thinner
  • thicker
  • tapering

Solution :

A concave lens is thicker at the edges.
Still have doubt? Watch Video
Q4. ________ produces real and inverted images. 
  • Plane mirror
  • Concave mirror
  • Convex mirror
  • Both a and b

Solution :

A concave mirror produces real and inverted images.
Still have doubt? Watch Video
Q5. The power of a lens in diopters is written as ______. 
  • All of these

Solution :

The power of a lens in diopters is written as .
Still have doubt? Watch Video
Q6. A convex lens has a focal length of 15 cm. An object must be placed at a distance of ________ in front of the convex lens so as to obtain an image which is real, inverted and of the same size.
  • 15 cm
  • infinity
  • 20 cm
  • 30 cm

Solution :

When the image formed by a convex lens is real, inverted and of the same size as the object, the distance of the object from the lens is 2f.   Since f = 15 cm 2f = 15 × 2 = 30 cm
Still have doubt? Watch Video
Q7. Magnification is _______ for a concave lens.
  • more than 1
  • equal to 1
  • more than 2
  • less than 1

Solution :

Magnification is less than 1 for a concave lens.
Still have doubt? Watch Video
Q8. __________ is/are the type of spherical mirror. 
  • Concave
  • Plane
  • Plano-convex
  • Both a and c

Solution :

Concave is/are the type of spherical mirror.
Still have doubt? Watch Video
Q9. If the ‘a’ is object distance, ‘b’ is image distance and ‘c’ is focal length of concave mirror. Then the mirror formula is written as __________.  

Solution :

If the ‘a’ is object distance, ‘b’ is image distance and ‘c’ is focal length of concave mirror. Then the mirror formula is written as
Still have doubt? Watch Video
Q10. In a glass slab, light gets refracted
  • once
  • twice
  • thrice
  • four times

Solution :

In a glass slab, light gets refracted twice. 
Still have doubt? Watch Video
Q11. A _____________ is also known as a converging mirror.  
  • Concave mirror
  • Convex mirror
  • Convex lens
  • Both B and C

Solution :

A concave mirror is also known as a converging mirror.
Still have doubt? Watch Video
Q12. When the angle of incidence is greater than the angle of refraction, the light ray 
  • passes from the rarer to the denser medium
  • passes from the denser to the rarer medium
  • undergoes reflection
  • Both a and c

Solution :

When the angle of incidence is greater than the angle of refraction, the light ray passes from the rarer to the denser medium.
Still have doubt? Watch Video
Q13. When reflected rays pass through the focus, the incident rays pass 
  • through the centre of curvature
  • parallel to the principal axis
  • through the principal focus
  • obliquely through the pole

Solution :

When reflected rays pass through the focus, the incident rays pass parallel to the principal axis.
Still have doubt? Watch Video
Q14. _________ is not a parameter of the difference in real image and virtual image. 
  • Screen
  • Nature of image
  • Type of mirror
  • Source of light

Solution :

Source of light is not a parameter of the difference in real image and virtual image.
Still have doubt? Watch Video
Q15. __________ is also known as a converging lens. 
  • Concave lens
  • Convex lens
  • Convex mirror
  • Both B and C

Solution :

A convex lens is also known as a converging lens. 
Still have doubt? Watch Video
Q16. The refractive index of a medium with respect to air is called
  • relative refractive index
  • grazing angle
  • absolute refractive index
  • refraction

Solution :

The refractive index of a medium with respect to air is called absolute refractive index.
Still have doubt? Watch Video
Q17. Which of the following is the correct mirror formula?
  • R(u + v) = 2uv
  • All of these

Solution :

All of three formulae are correct.  Solving the above equation R (u + v) = 2uv 
Still have doubt? Watch Video
Q18. In case of spherical lenses, all distances are measured from the
  • optical centre
  • direction of light
  • pole
  • zero point

Solution :

In case of spherical lenses, all distances are measured from the optical centre.
Still have doubt? Watch Video
Q19. If the image formed by a convex mirror is virtual, erect and diminished, then the object is placed
  • at the focus
  • between the focus and the centre of curvature
  • between infinity and the pole
  • at infinity

Solution :

If the image formed by a convex mirror is virtual, erect and diminished, then the object is placed between infinity and the pole.
Still have doubt? Watch Video
Q20. If an object is kept at a distance of 30 cm from the plane mirror, the image distance is
  • 15 cm
  • 20 cm
  • 60 cm
  • 30 cm

Solution :

If an object is kept at a distance of 30 cm from the plane mirror, the image distance is 30 cm. Object distance = image distance
Still have doubt? Watch Video