Two towers on top of two hills are 40 km apart. The line joining them passes 50 m above a hill halfway between the towers. What is the longest wavelength of radio waves, which can be sent between the towers without appreciable diffraction effects?

From the top of a tower, the angles of depression of two objects on the same side of the tower are found to be alpha and beta (alpha >beta) . If the distance between the objects is 'p' metres, show that the height 'h' of the tower is given by h=frac(p tan alpha tan beta)(tan alpha-tan beta) also determine the height of the tower, if p=50 m , alpha=60^@, beta=30^@

Two hagstaffs stand on a horizontal plane. A and B are two points on the line joining their feet and between them. The angles of elevation of the tops of the flagstaffs as seen from A are 30^@ and 60^@ and as seen from B are 60^@ and 45^@ . If AB is 30 m, then the distance between the flagstaffs is

To conduct Sports Day activities, in your rectangular shaped school ground ABCD, lines have been drawn with chalk powder at a distance of 1m each. 100 Flower pots have been placed at a distance of 1m from each other along AD, as shown in Fig. 7. 12. Niharika runs 1/4 th the distance AD on the 2nd line and posts a green flag. Preet runs 1/5th the distance AD on the eighth line and posts a red flag. What is the distance between both the flags? If Rashmi has to post a blue flag exactly halfway between the line segment joining the two flags, where should she post her flag?

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 small telescope has an objective lens of focal length 140 cm and an eyepiece of focal length 5.0 cm. (A) what is the separation between the objective lens and the eyepiece? (B) If this telescope is used to view a 100 m tall tower 3 km away, what is the height of the image of the tower formed by the objective lens?

A transmitting antenna at the top of a tower has a height 40m and the height of receiving antenna is 60m.What is the maximum distance between them for satisfactory communication in LOS mode? Given radius of earth is 6.4 xx10^6 m .