In torches, search lights and headlights of vehicles the bulb is placed [NCERT Exemplar Problems]

Question

In torches, search lights and headlights of vehicles the bulb is placed [NCERT Exemplar Problems]

Question

(a) between the pole and the focus of the reflector
(b) very near to the focus of the reflector
(c) between the focus and centre of curvature of
the reflector
(d) at the centre of curvature of the reflector

in progress 0

Class 10 science Rohit QNA 3 years 2021-11-20T17:46:11+00:00 2021-11-20T17:46:11+00:00 1 Answer 11 views Enlightened 0

About Rohit QNAEnlightened

Related questions

What is area sown more than once in an agriculture year plus net sown area known as?
Rohan wants to measure the distance of a pond during the visit to his native. He marks points A and B on the opposite edges of a pond as shown in the figure below. To find the distance between the points, he makes a right-angled triangle using rope connecting B with another point C are a distance of 12m, connecting C to point D at a distance of 40m from point C and the connecting D to the point A which is are a distance of 30m from D such the ∠ADC=900.Find the length of the rope used.
Reactive metals can displace less reactive metals from their compounds in solution or molten form. all metals are not equally reactive. We checked the reactivity of various metals with oxygen, water and acids. But all metals do not react with these reagents. Displacement reactions give better evidence about the reactivity of metals. It is simple and easy if metal A displaces metal B from its solution, it is more reactive than B. The reactivity series is a list of metals arranged in the order of their decreasing activities.
You must have observed that iron articles are shiny when new, but get coated with a reddish brown powder when left for some time. This process is commonly known as rusting of iron. Some other metals also get tarnished in this manner. Have you noticed the colour of the coating formed on copper and silver? When a metal is attacked by substances around it such as moisture, acids, etc., it is said to corrode and this process is called corrosion. The black coating on silver and the green coating on copper are other examples of corrosion
All metals do not react with oxygen at the same rate. Different metals show different reactivities towards oxygen. Metals such as potassium and sodium react so vigorously that they catch fire if kept in the open. Hence, to protect them and to prevent accidental fires, they are kept immersed in kerosene oil. At ordinary temperature, the surfaces of metals such as magnesium, aluminium, zinc, lead, etc., are covered with a thin layer of oxide. The protective oxide layer prevents the metal from further oxidation. Iron does not burn on heating but iron filings burn vigorously when sprinkled in the flame of the burner. Copper does not burn, but the hot metal is coated with a black coloured layer of copper(II) oxide. Silver and gold do not react with oxygen even at high temperatures.

Answer ( 1 )

Leave an answer

Previous question

Next question

Rohit QNA Enlightened · Answer 1 · 2021-11-20T17:46:38+00:00

Rohit QNA Enlightened

0

2021-11-20T17:46:38+00:00 November 20, 2021 at 5:46 pm

Reply

Answer: b
Explanation:
(b) When source of light is placed very
near to the focus of the reflector which
are concave in shape, the reflected light
becomes parallel to the principal axis

Register Now

Login

Lost Password

Add question

Login

Register Now

In torches, search lights and headlights of vehicles the bulb is placed [NCERT Exemplar Problems]