What is the relation between the refractive index of water with respect to air μ w a , and the refractive index of air with respect to water μ a w .

When light moves from one transparent medium to another and none of the medium is air or vacuum, the relative refractive index of second medium with respect to first is defined as, μ 2 1 = 1 μ 1 2 So, the relationship between the refractive index of water with respect to air ( μ w a ) and the refractive index of air with respect to water μ a w is μ w a = 1 μ a w

If the refractive index of water with respect to air ( μ w a ) is 5 3 . Calculate the refractive index of air with respect to water ( μ a w ).

Given that, Refractive index of water with respect to air is μ w a = 5 3 We know that water and air are two different media, water is denser whereas air is a rarer medium. The refractive index of the denser medium is always greater than 1 . Therefore, the refractive index of air with respect to water is w μ a = 1 a μ w = 1 5 / 3 = 3 5

The diagram below shows a magnetic needle kept just below the conductor AB which is kept in the North-South direction. i) In which direction will the needle deflect when the key is closed? ii) Why is the deflection produced? iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB? iv) Name one device which works on this principle.

According to the Right-Hand Thumb Rule for the magnetic field, when we hold a current-carrying conductor in the right hand, where the thumb points towards the direction of the current. When we wrap the fingers around the conductor, the fingers point towards the direction of the magnetic field lines. i) In the first case, when the key is closed the current is from B to A. So, as per the right-hand thumb rule just below the conductor, the direction of the magnetic field is towards east. So, due to this needle will deflect towards east. ii) The deflection is produced due to the magnetic field created when current is passed through the wire. iii) In the second case when a magnetic needle is kept just above the conductor when the key is closed the current direction will reverse i.e. from B to A. So, applying right-hand thumb rule just above the conductor, the direction of the magnetic field generated is towards west. So, the needle will deflect towards the West. iv) A device that works on this principle is a magnetic sensor.

Rewrite and complete the following nuclear reaction by filling in the atomic number of Ba and mass number of Kr: U 92 235 + n 0 1 → Ba _ _ _ 144 + Kr 36 _ _ _ + 3 n 0 1 + Energy

For the better understanding of nuclear reaction, a sample of uranium is bombarded with neutrons in an attempt to produce new elements with Z < 92 . It has been observed that lighter elements (lower atomic number) such as Barium ( Z = 56 ) are formed during the reaction and releases heat. U 92 235 + n 0 1 → Ba 56 144 + Kr 36 88 + 3 n 0 1 + Energy

Define nuclear fission.

Nuclear fission is an exothermic reaction process, in which a heavier atom splits into lighter nuclei. This elemental transmutation can be natural spontaneous splitting by radioactive decay, or can actually be stimulated in a lab by achieving necessary conditions (bombarding) with the resulting nuclei tend to have a combined mass which is less than the original. The missing mass is converted into nuclear energy in the nuclear reaction.

Draw a neat labeled diagram of an A.C. generator.

An A.C. generator is a device that converts mechanical energy into electrical energy and produce electricity. It works based on electromagnetic induction.

If 104 g of water at 30 ° C is taken in a calorimeter made of copper of mass 42 g . When a certain mass of ice at 0 ° C is added to it, the final steady temperature of the mixture after the ice has melted, was found to be 10 ° C . Find the mass of ice added. (Specific heat capacity of water = 4 . 2 J g - 1 ° C - 1 , Specific latent heat of fusion of ice = 336 J g - 1 , Specific heat capacity of copper = 0 . 4 J g - 1 ° C - 1 )

Data Given, Mass of water m 1 = 104 g , temperature of water T 1 = 30 ° C , final temperature T 2 = 10 ° C , mass of calorimeter m 2 = 42 g , temperature of ice T 3 = 0 ° C , specific heat capacity of water S w = 4 . 2 J g - 1 ° C - 1 , specific latent heat of fusion of ice L = 336 J g - 1 , specific heat capacity of copper S c = 0 . 4 J g - 1 ° C - 1 . Let the mass of ice added be m = x , According to the principle of calorimetry, total heat energy lost is equal to total heat gain. ⇒ m 1 S w T 1 - T 2 + m 2 S c T 1 - T 2 = mL + mS w T 2 - T 3 By substituting the given values we get, 104 × 4 . 2 × 20 + 42 × 0 . 4 × 20 = 336 x + x 4 . 2 × 10 8736 + 336 = 378 x x = 9072 378 = 24 g . Hence, the mass added is 24 g .

The melting point of naphthalene is 80 ° C and the room temperature is 30 ° C . A sample of liquid naphthalene at 100 ° C is cooled down to the room temperature. Draw a temperature time graph to represent this cooling. In the graph, mark the region which corresponds to the freezing process.

As naphthalene is having melting point at 80 ° C , in this zone due to the latent heat of fusion the temperature remains steady at 79 ° C (Freezing point of napthalene) as the napthalene solidifies as shown by the portion BC of the curve. This happens even though thermal energy is being lost to the surroundings. There is no change in temperature. This is basically Freezing process zone.

Name the material used for making a Calorimeter. Why is a Calorimeter made up of thin sheets of the this material?

The Calorimeter box is made up of Copper. A calorimeter is a device used to measure the quantity of heat transferred to or from an object. Cu is highly malleable, and hence very thin box of small mass can be made. Copper is a good conductor of heat. Calorimetry is the process of measuring the amount of heat released or absorbed during a chemical reaction. A calorimeter box is made up of Copper because (i) Cu has low specific heat capacity, and thus it reaches the equilibrium temperature quickly by absorbing a small amount of heat. (ii) Cu is highly malleable and hence a very thin box of small mass can be made thus decreasing the heat capacity of the box. This makes sure the calorimeter absorbs or liberates a small amount of heat during the heat exchange.

Calorimetry is the study that related with determining the changes in energy of a system by measuring the heat exchanged with the surroundings and by this holding the law of conservation of energy.

E M B I B E

Self Study in Physics>Chapter 14 - Latest ICSE Examination Question Paper-2019 (Solved)>SCIENCE PAPER - I (PHYSICS)>Q 1

MEDIUM

10th ICSE

IMPORTANT

Earn 100

Define couple. State the SI unit of moment of couple.

Important Questions on Latest ICSE Examination Question Paper-2019 (Solved)

EASY

10th ICSE

IMPORTANT

Self Study in Physics>Chapter 14 - Latest ICSE Examination Question Paper-2019 (Solved)>SCIENCE PAPER - I (PHYSICS)>Q 1

State the SI unit of moment of couple?

EASY

10th ICSE

IMPORTANT

Self Study in Physics>Chapter 14 - Latest ICSE Examination Question Paper-2019 (Solved)>SCIENCE PAPER - I (PHYSICS)>Q 1

Define critical angle.

EASY

10th ICSE

IMPORTANT

Self Study in Physics>Chapter 14 - Latest ICSE Examination Question Paper-2019 (Solved)>SCIENCE PAPER - I (PHYSICS)>Q 1

State one important factor which affects the critical angle of a given medium.

MEDIUM

10th ICSE

IMPORTANT

Self Study in Physics>Chapter 14 - Latest ICSE Examination Question Paper-2019 (Solved)>SCIENCE PAPER - I (PHYSICS)>Q 2

An electromagnetic radiation is used for photography in fog.
(i) Identify the radiation.
(ii) Why is this radiation mentioned by you, ideal for this purpose?

EASY

10th ICSE

IMPORTANT

Self Study in Physics>Chapter 14 - Latest ICSE Examination Question Paper-2019 (Solved)>SCIENCE PAPER - I (PHYSICS)>Q 2

What is the relation between the refractive index of water with respect to air $({}_{a}μ_{w})$ , and the refractive index of air with respect to water $({}_{w}μ_{a})$ .

EASY

10th ICSE

IMPORTANT

Self Study in Physics>Chapter 14 - Latest ICSE Examination Question Paper-2019 (Solved)>SCIENCE PAPER - I (PHYSICS)>Q 2

If the refractive index of water with respect to air ( ${}_{a}μ_{w}$ ) is $\frac{5}{3}$ . Calculate the refractive index of air with respect to water ( ${}_{w}μ_{a}$ ).

MEDIUM

10th ICSE

IMPORTANT

Self Study in Physics>Chapter 14 - Latest ICSE Examination Question Paper-2019 (Solved)>SCIENCE PAPER - I (PHYSICS)>Q 2

The specific heat capacity of a substance

A

is

3, 800 J {kg}^{- 1} K^{- 1}

and that of a substance

B

is

400 J {kg}^{- 1} K^{- 1}

. Which of the two substances is a good conductor of heat? Give a reason for your answer.

MEDIUM

10th ICSE

IMPORTANT

Self Study in Physics>Chapter 14 - Latest ICSE Examination Question Paper-2019 (Solved)>SCIENCE PAPER - I (PHYSICS)>Q 2

A man playing a flute is able to produce notes of different frequencies. If he closes the holes near his mouth, will the pitch of the note produced, increase or decrease? Give a reason.

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