Tag: evs

Questions Related to evs

Amount of light reflected depends upon

evs reflection of light by plane surfaces characteristics of an image formed by a plane mirror formation of image in a plane mirror characteristics of the image formed by a plane mirror

  1. Nature of material of the object

  2. Nature of the surface

  3. Smoothness of the surface

  4. All of these

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Correct Option: D
Explanation:

Amount of light reflected depends upon nature of material of the object, nature of the surface and smoothness of the surface. If the material is opaque for an incident light, then the total amount of incident light gets reflected. Otherwise, a part of the incident light can get transmitted.  If the surface is smooth, the reflection is more, otherwise reflected light can get scattered. 

Which type of an image is formed by a plane mirror?

evs reflection of light by plane surfaces characteristics of an image formed by a plane mirror formation of image in a plane mirror characteristics of the image formed by a plane mirror

  1. Real & inverted

  2. Real & erect

  3. Virtual & erect

  4. Virtual & inverted

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Correct Option: D
Explanation:

The image that is formed by a plane mirror will be virtual, upright, same size and inverted

The object distance and the image distance will be equal.

Thus, the image formed by a plane mirror is virtual and inverted.

Image formed by a plane mirror is
a) of same size as that of object
b) at the same distance behind the mirror as the object in front
c) erect, virtual
Mark the correct statements:

evs reflection of light by plane surfaces characteristics of an image formed by a plane mirror formation of image in a plane mirror characteristics of the image formed by a plane mirror

  1. a and b

  2. b and c

  3. a and c

  4. All

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Correct Option: D
Explanation:

Image formed by a plane mirror is of same size as that of object and is formed at the same distance behind the mirror as object is in front of the mirror.

And the image formed is virtual, erect and laterally inverted.

Answer-(D)

Who among the following is the author of the famous book "Silent Spring" which is credited for being of much help in launching the environment movement?

evs natural calamities disaster and types disasters forest fire

  1. Ian Lowe

  2. Pat Hutchings

  3. Mike Kingsford

  4. Rachel Carson

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Correct Option: D

In an experiment, 2.4 g of iron oxide on reduction with hydrogen gave 1.68 g of iron. In another experiment, 2.9 g of iron oxide gave 2.09 g of iron on reduction. Which law is illustrated from the above data?

evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

  1. Law of constant proportions

  2. Law of multiple proportions

  3. Law of reciprocal proportions

  4. Law of conservation of mass

Show answer
Correct Option: A
Explanation:
In experiment 1,
$2.4\ g$ of iron oxide gives $1.68\ g$ iron on reduction with hydrogen.
$FeO \rightarrow Fe+O _2$
Percent of $Fe$ in $FeO$ is = $\frac{1.68}{2.4} \times 100=70$
Therefore ratio of $m _{Fe}:m _{O}::7:3$
In experiment 2:
$2.9\ g$ of iron oxide gives $2.09\ g$ iron on reduction.
Percent of $Fe$ in $FeO$ is = $\frac{2.09}{2.9} \times 100=72$

Therefore ratio of $m _{Fe}:m _{O} \approx 7:3$
When a given chemical compound contains its component elements in fixed ratio (by mass) and does not depend on its source and method of preparation, it follows law of constant proportion.
option A is correct

A sample of calcium carbonate $(CaCO _{3})$ has the following percentage composition:
Ca = 40%; C = 12%; O = 48%.
If the law of constant proportions is true, then the weight of calcium in 4 g of a sample of calcium carbonate from another source will be:

evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

  1. 0.016 g

  2. 0.16 g

  3. 1.6 g

  4. 16 g

Show answer
Correct Option: C
Explanation:

In $100$ $g$ $CaCO _3$, $40$ $g$ $Ca$ is present.

In $4$ $g$ $CaCO _3$, Let $x$ $g$ $Ca$ be present
$\cfrac{x}{4}=\cfrac{40}{100}$
$\implies x=1.6$ $g$

A sample of calcium carbonate $\left( CaC{O} _3 \right)$ has the following percentage composition:
Ca = 40%; C = 12%; O = 48%.
If the law of constant proportions is true, then the weight of calcium in 4 g of a sample of calcium carbonate from another source will be ?

evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

  1. 0.016 g

  2. 0.16 g

  3. 1.6 g

  4. 16 g

Show answer
Correct Option: C
Explanation:

Calcium carbonate from any source contains 40% calcium. 

So each 1 g of calcium carbonate contains 0.4g of calcium.
Thus, for 4 g of calcium carbonate, the amount of calcium $=4\times 0.4=1.6g$

Different samples of water were found to contain hydrogen and oxygen in the ratio of 1 : 8. This shows the law of:

evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

  1. multiple proportions

  2. constant proportions

  3. reciprocal proportions

  4. conservation of mass

Show answer
Correct Option: B
Explanation:

Law of Constant proportion states that a chemical compound always contains same elements combined together in the same proportion by mass.

All samples of carbon dioxide contain carbon and oxygen in the mass ratio of $3 : 8$. This is in agreement with the law of :

evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

  1. conservation of mass

  2. constant proportion

  3. multiple proportions

  4. gaseous volumes

Show answer
Correct Option: B
Explanation:

LAW OF CONSTANT OR DEFINITE PROPORTION : It was given by Proust.
It states that all chemical compounds are found to have constant composition irrespective of their method of preparation or sources.
THE LAW OF MULTIPLE PROPORTION : It was given by Dalton.
It states that when one element combines with the other element to form two or more different compounds, the mass of one element which combines with a constant mass of the other bear a simple ratio to one another.

Law of constant composition is also called as the law of :

evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

  1. Conservation of mass

  2. Conservation of energy

  3. Multiple proportion

  4. Definite proportion

Show answer
Correct Option: D
Explanation:

Law of constant composition is also called as the law of Definite proportion which says that the law of constant composition is a chemistry law which states samples of a pure compound always contain the same elements in the same mass proportion.