The diagram shows a dish antenna which is used to receive televisiton signals form a satellite. The antenna (signal detector ) is fixed forn of the curved dish .

What is the shape of the 'dish' of a dish antenna used for receiving TV signals from a satellite ?

find the minimum colatitude which can directly receive a signal from a geostationary satellite.

Name the device fitted in the satellite which receives signals from Earth station and transmits them in different directions after amplification.

The diagram shows the sketch of an electrolytic cell used in the extraction of aluminium. At which electrode (A or B) is the aluminium formed?

A carrier wave of 2000 kHz is used to carry the signal, the length of the transmitting antenna will be equal to

Two radio stations broadcast their programmes at the same amplitude A and at slightly different frequencies omega_(1) and omega_(2) respectively, where omega_(1) - omega_(2) = 10^(3) Hz A detector receives the signals from the two stations simultaneously. it can only detect signals of intensity ge 2A^(2) . (i) Find the time interval between successive maxima of the intensity of the signal received by the detector. (ii) Find the time for which the detector remains idle in each cycle of the intensity of the signal.

A radio station broadcasting at a frequency of 1500 kHz gerertes a directional beam by using an array of 4 point ource antennas driver in phase with each other by the same transmitter. The antennas are arranged along an east west line so that each antenna is 50m from the next one. (a) In what direction will be radiated signal to greatest ? (b) How mcuh signal radiates in east west direction.

Height h(400=m) from the ground at place A, from which the readiowaves can be transmitted. There is a receive at station B on earth at a distance d(=125km), which can receive the signal from station A. The radiowaves can reach the station B, either through earth's atmosphere or through satellite. There are four main layers in earth's atmosphere named D,E, F_(1) and F_(2) which play effective role in radio communication. The electron density of these layers is 4xx10^(8), 2xx10^(11),5xx10^(11) and 8xx10^(11)m^(-3) . The radius of the earth is 6.4xx10^(6)m . If the station A sends the T.V. signals, then the maximum area on earth upto which T.V. transmission can be received on earth is (average population density around the tower is 1000 km^(-2) )