A person needs a lens of power –5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near vision?
Power of the lens is given (P) for distant vision = -5.5 D
Power of the lens (P2) is given for near vision = + 1.5 D
1. Focal length of the lens required for correcting lens of distant vision
Formula used, P = 1/ f where, P is the power of the lens
And, f is the focal length
To correct f
f = 1/ P
f = 1/ -5.5
f = - 0.1818 m.
2. Focal length of the lens required for correcting lens of near vision
Formula used, P = 1/ f where, P is the power of the lens
And, f is the focal length
To correct f
f = 1/ P
f = 1/ 1.5
f = - 0.667 m.
Popular Questions of Class 10 Science
- Q:-
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
- Q:-
Outline a project which aims to find the dominant coat colour in dogs.
- Q:-
Draw the structure for the following compounds.
(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal.*Are structural isomers possible for bromopentane?
- Q:-
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?
- Q:-
How is the sex of the child determined in human beings?
- Q:-
(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common? - Q:-
Calculate the number of electrons constituting one coulomb of charge.
- Q:-
What is an homologous series? Explain with an example.
- Q:-
Why is variation beneficial to the species but not necessarily for the individual?
- Q:-
A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?
Recently Viewed Questions of Class 10 Science
- Q:-
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
- Q:-
One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.
- Q:-
What is the role of saliva in the digestion of food?
- Q:-
What is a balanced chemical equation? Why should chemical equations be balanced?
- Q:-
Define the unit of current.
- Q:-
What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?
- Q:-
Outline a project which aims to find the dominant coat colour in dogs.
- Q:-
Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V.
- Q:-
What is the role of decomposers in the ecosystem?
- Q:-
Why don’t two magnetic field lines intersect each other?
- NCERT Chapter