The term critical frequency denotes _________.

(a) the lowest frequency that is reflected by the ionosphere at vertical distance
(b) the highest frequency that is reflected by the ionosphere at vertical distance
(c) the lowest frequency by which communication is possible between two given points
(d) none of the above

Ans: B

Comments

Post a Comment

Popular posts from this blog

Top 30 Electrical Switchgear & Protection Interview Questions with Answers PDF

Image
Real Time Electrical Switchgear & Protection Interview Questions with Answers PDF 1. What are the main functions of control gear? 1. To provide a means of starting and stopping the motor and, at the same time, of limiting the starting current if required. 2. To give adequate protection to the motor under all conditions. 3. To allow speed changing when required. 4. To provide means of braking the motor when required. 5. To reverse the direction of rotation when required. Protection of the motor must be automatic, but the other operations may be arranged to be under the control of an operator, or may be partly or fully-automatic. 2. What provision must be made for short-circuit conditions in motor circuits? Since overload relays are not designed to operate and clear the circuit in the event of a short-circuit. Circuit-breaker or fuse protection of suficient breaking capacity to deal with any possible short-circuit that may occur must be provided. 3. What are the usual forms of overlo...
Read more

50 TOP Irrigation Engineering Interview Questions & Answers pdf

Here are top 50 Irrigation Engineering Interview questions and answers are given just below to them. These sample Irrigation Engineering questions are framed by experts. who train for Learn Irrigation Engineering Online to give you an idea of Irrigation Engineering questions which may be asked in interview. We have taken full care to give correct answers for all the questions. Do comment your thoughts. Happy Job Hunting! 1. Why Are Landscapes Irrigated? Simply stated, irrigation provides the water requirements for sustainability of plants when rainfall is not sufficient. Ornamentals: Trees and shrubs are irrigated frequently when grown in the nursery and when first planted so that their roots quickly grow out from the root ball and into the soil in the landscape. It is crucial that roots grow as quickly as possible so irrigation can cease. The best way to encourage rapid root growth is frequent light irrigation applied to the root ball after planting. Under ideal con...
Read more