A 2.0 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 10 cm. The distance of the object from the lens is 15 cm. Find the nature, position and size of the image. Also find its magnification.

Explain the following
(a) Reactivity of Al decreases if it is dipped in HNO₃.
(b) Carbon cannot reduce the oxides of Na or Mg
(c) NaCl is not a conductor of electricity in solid state whereas it does conduct electricity in aqueous solution as well as in molten state.
(d) Iron articles are galvanised 
(e) Metals like Na, K, Ca and Mg are never found in their free state in nature.

Samples of four metals A, B, C and D were taken and added to the following solution one by one. The result obtained have been tabulated as follows :

Use the given table above to answer the following questions about metals A, B, C and D
(i) Which is the most reactive metal?
(ii) What would you observed if B is added to a solution of copper (II) sulphate?
(iii) Arrange the metals A, B, C and D in the order of decreasing reactivity.

Under which of the following conditions a concave mirror can form an image larger than the actual object?

Where should an object be placed in front of a convex lens to get a real image of the size of the object?

Which one of the following four metals would be displaced from the solution of its salts by other three metals?

Aluminium is used for making cooking utensils. Which of the following properties of aluminium are responsible for the same?

(i) Good thermal conductivity

(ii) Good electrical conductivity

(iii) Ductility

(iv) High melting point

Which of the following pairs will give displacement reactions?

Name the metal which reacts with a very dilute HNO₃ to evolve hydrogen gas.

"A ray of light incident on a rectangular glass slab immersed in any medium emerges parallel to itself." Draw a labelled ray diagram to justify the statement?

State mirror formula. How does of change when object distance u from the mirror is changed?

The following reaction takes place when aluminium powder is heated with MNO₂
\({ 3MnO }_{ 2 }+4Al(s)\rightarrow 3Mn(l)+{ 2Al }_{ 2 }{ O }_{ 3 }+Heat\)
(a) Is aluminium getting reduced?
(b) Is MnO₂ getting oxidised?

A metal is found in liquid state. It is widely used in instrument for measuring blood pressure. In what form does it occur in nature? How can we extract this metal from its ore?

Assertion: Keeping a point object fixed, if a plane mirror is moved, the image will also move.
Reason : In case of a plane mirror, distance of object and its image is equal from any point on the mirror.
Codes
(a) Both A and R are true, and R is correct explanation of the assertion.
(b) Both A and R are true, but R is not the correct explanation of the assertion.
(c) A is true, but R is false.
(d) A is false, but R is true.

Assertion: We can decide the nature of a mirror by observing the size of erect image in the mirror.

Reason: The minimum distance between a real object and its real image in a concave mirror is non zero.
Codes
(a) Both A and R are true, and R is correct explanation of the assertion.
(b) Both A and R are true, but R is not the correct explanation of the assertion.
(c) A is true, but R is false.
(d) A is false, but R is true

Assertion: The dentists use convex mirrors to see large images of the teeth of patients.
Reason: The convex mirrors always produces the enlarged image of the object.
Codes
(a) If both assertion and reason are true and the reason is correct explanation of assertion.
(b) If both assertion and reason are true but reason is not a correct explanation of assertion. -.
(c) If assertion is true and reason is false.
(d) If both assertion and reason are false.

Assertion: Alloy is made by mixing a metal with either other metal or non metal
Reason: It is prepared by first melting the primary metal and then dissolving the other elements in it in definite proportions.
Codes
(a) If both assertion and reason are true and the reason is correct explanation of assertion.
(b) If both assertion and reason are true but reason is not a correct explanation of assertion.
(c) If assertion is true and reason is false.
(d) If both assertion and reason are false.

Assertion: Iron does not bum on heating
Reason: Iron filings bum vigorously when sprinkled in the flame of the burner.
Codes
(a) If both assertion and reason are true and the reason is correct explanation of assertion.
(b) If both assertion and reason are true but reason is not a correct explanation of assertion.
(c) If assertion is true and reason is false.
(d) If both assertion and reason are false.

The lenses forms different types of images when object placed at different locations. When a ray is incident parallel to the principal axis, then after refraction, it passes through the focus or appears to come from the focus. When a ray goes through the optical centre of the lens, it passes without any deviation.
If the object is placed between focus and optical center of the convex lens, erect and magnified image is formed. As the object is brought closer to the convex lens from infinity to focus, the image moves away from the convex lens from focus to infinity. Also the size of image goes on increasing and the image is always real and inverted. A concave lens always gives a virtual, erect and diminished image irrespective to the position of the object.
(i) The location of image formed by a convex lens when the object is placed at infinity is

(ii) When the object is placed at the focus of concave lens, the image formed is

(iii) The size of image formed by a convex lens when the object is placed at the focus of convex lens is

(iv) When the object is placed at 2F in front of convex lens, the location of image is

When the rays of light travels from one transparent medium to another, the path of light is deviated. This phenomena is called refraction of light. The bending of light depends on the optical density of medium through which the light pass.

The speed of light varies from medium to medium. A medium in which the speed of light is more is optically rarer medium whereas in which the speed of light is less is optically denser medium. Whenever light goes from one medium to another, the frequency of light does not change however, speed and wavelength change. It concluded that change in speed of light is the basic cause of refraction.
(i) When light travels from air to glass, the ray of light bends

(ii) A ray of light passes from a medium A to another medium B. No bending of light occurs if the ray of light hits the boundary of medium B at an angle of

(iii) When light passes from one medium to another, the frequency of light

(iv) When light passes from glass to water, the speed of light

(v) The bottom of pool filled with water appears to be ______ due to refraction of light

The spherical mirror forms different types of images when the object is placed at different locations.
When the image is formed on screen, the image is real and when the image does not form on screen, the image is virtual. When the two reflected rays meet actually, the image is real and when they appear to meet, the image is virtual.
A concave mirror always forms a real and inverted image for different positions of the object. But if the object is placed between the focus and pole, the image formed is virtual and erect.
A convex mirror always forms a virtual, erect and diminished image. A concave mirror is used as doctor's head mirror to focus light on body parts like eyes, ears, nose etc., to be examined because it can form erect and magnified image of the object. The convex mirror is used as a rear view mirrors in automobiles because it can form an small and erect image of an object.
(i) When an object is placed at the centre of curvature of a concave mirror, the image formed is

(ii) No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be

(iii) A child is standing in front of a magic mirror. She finds the image of her head bigger, the middle portion of her body of the same size and that of the legs smaller. The following is the order of combinations for the magic mirror from the top.

(iv) To get an image larger than the object, one can use
(a) convex mirror but not a concave mirror
(b) a concave mirror but not a convex mirror
(c) either a convex mirror or a concave mirror
(d) a plane mirror.
(v) A convex mirror has wider field of view because
(a) the image formed is much smaller than the object and large number of images can be seen
(b) the image formed is much closer to the mirror
(c) both (a) and (b)
(d) none of these.

On the basis of reactivity of different metals with oxygen, water and acids as well as displacement reactions, the metals have been arranged in the decreasing order of their reactivities. This arrangement is known as activity series or reactivity series of metals.
The basis of reactivity is the tendency of metals to lose electrons. If a metal can lose electrons easily to form positive ions, it will react readily with other substances. Therefore, it will be a reactive metal. On the other hand, if a meal loses electrons less rapidly to form a positive ion, it will react slowly with other substances. Therefore, such a metal will be less reactive.
(i) Which of the following metals is less reactive than hydrogen?

(ii) Which of the following metals is more reactive than hydrogen?

(iii) Which of the following metals reacts vigorously with oxygen?

(iv) Which of the following represents the correct order of reactivity for the given metals?

(v) Hydrogen gas is not evolved when a metal reacts with nitric acid. It is because HNO₃ is a strong oxidising agent. It oxidises the H₂ produced to water and itself gets reduced to any of the nitrogen oxides (N₂O, NO, NO₂ ). But ___________ and ___________ react with very dilute HNO₃ to evolve H₂ gas.

The chemical reactivity of an element depends upon its electronic configuration. All elements having less than eight electrons in the outermost shell show chemical reactivity. During chemical reactions, atoms of all elements tend to achieve a completely filled valence shell. Metals are electropositive in nature. They have tendency to lose one or more electrons present in the valence shell of their atoms to form cations and achieve nearest noble gas configuration. The compounds formed by the transfer of electrons from one element to other are known as ionic or electrovalent compounds.
(i) The electronic configurations of three elements X, Y and Z are:
            X : 2                  Y: 2, 8, 7                     Z : 2, 8, 2
Which of the following is correct regarding these elements?

(ii) Element X reacts with element Y to form a compound Z. During the formation of compound Z, atoms of X lose one electron each whereas atoms of Y gain one electron each. Which of the following properties is not shown by compound Z?

(iii) Which of the following is correct representation of formation of magnesium chloride?

	(d) None of these

(iv) The electronic configuration of sodium ion is

(v)Which of the following represents an electropositive element?