Consider a sunlike start at a distance of 2 parsecsWhen it is seen through a telescope with 100 magnification, what should be the angular size of the star? Sun appears to be `(1//2)^@` from the earth. Due to atmospheric fluctuationsw, eye can't resolve objects smaller than 1 arc minute.

The earth- moon distance is about 60 earth radius. Moon is seen to be of (1//2)^@ diameter from the earth. What must be the relative size compared to the earth?

Mars has approximately half of the earth's diameter. When it is closest to the earth it is at abot 1/2 A.U. from the earth. Calculate what size it will appear when seen through the same telescope.

A telescope has an objective of diameter of 60 cm. The focal lengths of the objective and eye piece are 2.0 m and 1.0 cm respectively. The telescope is directed to view two distant almost point sources of light (e.g. two stars of a binary). The sources are at roughly the same distance (=10^4 light years) along the line of sight but separated transverse to the line of sight by a distnace of 10^10 m . what will the telescope resolve the two objects i.e. will it see two distinct stars?

A card sheet divided into squares each of size 1 mm^2 is being viewed at a distance of 9 cm through a magnifying glass (a converging lens of focal length 10 cm) held close to the eye. What should be the distance between the object in converging lens and the magnifying glass if the virtual image of each square in the figure is to have an area of 6.25 mm^2 . Would you be able to see the squares distinctly with your eyes very close to the magnifier ?

A colloidal solution is a type of mixture which consists of particles whose size varies between 1 and 1000 nanometres. In colloidal solution the particles are distributed evenly. During this process the particles do not settle down. This is one of the best know thing about colloidal solutions. Properties of colloids and their variation are a well-known area ever since the primitive age. The best example to prove their familiarity with us is that we know from very early times that coagulation of milk results in the formation of curd. Physical properties of colloids 1. The nature of the colloidal solution is heterogeneous i.e. unlike. These solutions dwell with two different phases : • Dispersed medium Dispersed phase. 2. Despite the fact that colloidal dispersions are unlike in description (nature), yet the dispersed fragments are not detectable by the human eye. This is due to the microscopic size of the particles in the solution. 3. The colour of the colloidal dispersion is determined by particles in the solution based on their size. The wavelengths of light that is absorbed will be longer ifthe size of the particle is large. 4. As a result of its size, the colloidal fragments can easily be passed through a traditional filter paper. However, these particles can be filtered by using membranes such as animal, cellophane, and ultrafilters. What are colloidal solution particle.

A colloidal solution is a type of mixture which consists of particles whose size varies between 1 and 1000 nanometres. In colloidal solution the particles are distributed evenly. During this process the particles do not settle down. This is one of the best know thing about colloidal solutions. Properties of colloids and their variation are a well-known area ever since the primitive age. The best example to prove their familiarity with us is that we know from very early times that coagulation of milk results in the formation of curd. Physical properties of colloids 1. The nature of the colloidal solution is heterogeneous i.e. unlike. These solutions dwell with two different phases : • Dispersed medium Dispersed phase. 2. Despite the fact that colloidal dispersions are unlike in description (nature), yet the dispersed fragments are not detectabJe by the human eye. This is due to the microscopic size of the particles in the solution. 3. The colour of the colloidal dispersion is determined by particles in the solution based on their size. The wavelengths of light that is absorbed will be longer ifthe size of the particle is large. 4. As a result of its size, the colloidal fragments can easily be passed through a traditional filter paper. However, these particles can be filtered by using membranes such as animal, cellophane, and ultrafilters. What type of phases of colloidal solutions ?

A colloidal solution is a type of mixture which consists of particles whose size varies between 1 and 1000 nanometres. In colloidal solution the particles are distributed evenly. During this process the particles do not settle down. This is one of the best know thing about colloidal solutions. Properties of colloids and their variation are a well-known area ever since the primitive age. The best example to prove their familiarity with us is that we know from very early times that coagulation of milk results in the formation of curd. Physical properties of colloids 1. The nature of the colloidal solution is heterogeneous i.e. unlike. These solutions dwell with two different phases : • Dispersed medium Dispersed phase. 2. Despite the fact that colloidal dispersions are unlike in description (nature), yet the dispersed fragments are not detectabJe by the human eye. This is due to the microscopic size of the particles in the solution. 3. The colour of the colloidal dispersion is determined by particles in the solution based on their size. The wavelengths of light that is absorbed will be longer ifthe size of the particle is large. 4. As a result of its size, the colloidal fragments can easily be passed through a traditional filter paper. However, these particles can be filtered by using membranes such as animal, cellophane, and ultrafilters. Give the name of membrane used for filteration ?

A card sheet divided into squares each of size 1 mm^2 is being viewed at a distance of 9 cm through a magnifying glass (a converging lens of focal length 9 cm) held close to the eye. What is the angular magnification (magnifying power) of the lens?

A card sheet divided into squares each of size 1 mm^2 is being viewed at a distance of 9 cm through a magnifying glass (a converging lens focal length 10 cm) held close to the eye. What is the magnification produced by the lens? How much is the area of each square in the virtual image?

In each of the following problems, clearly state what the relevant and irrelevant factors are while going through Steps 1, 2 and 4 given in this chapter :- Suppose a car starts from a place A and travels at a speed of 40 km/h towards another place B. At the same instance, another car starts from B and travels towards A at a speed of 30 km/h. If the distance between A and B is 100 km, after how much time will the cars meet?