KCET · Physics · Communication System
The radius of the Earth is \( 6400 \mathrm{~km} \). If the height of the antenna is \( 500 \mathrm{~m} \) then its range is
- A \( 800 \mathrm{~km} \)
- B \( 100 \mathrm{~km} \)
- C \( 80 \mathrm{~km} \)
- D \( 10 \mathrm{~km} \)
Answer & Solution
Correct Answer
(C) \( 80 \mathrm{~km} \)
Step-by-step Solution
Detailed explanation
Given, radius of Earth, \(R=6400 \mathrm{~km}\); height of antenna \(=500 \mathrm{~m}=500 \times 10^{-3} \mathrm{~km}\)
Now, range of antenna \(=\sqrt{2 R h}\)
\(=\sqrt{2 \times 6400} \times 500 \times 10^{-3} \mathrm{~km}\)
\(=\sqrt{64 \times 100}=80 \mathrm{~km}\)
Therefore, range of antenna \(=80 \mathrm{~km}\)
Now, range of antenna \(=\sqrt{2 R h}\)
\(=\sqrt{2 \times 6400} \times 500 \times 10^{-3} \mathrm{~km}\)
\(=\sqrt{64 \times 100}=80 \mathrm{~km}\)
Therefore, range of antenna \(=80 \mathrm{~km}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- Two parallel wires in free space are \(10 \mathrm{~cm}\) apart and each carries a current of \(10 \mathrm{~A}\) in the same direction. The force exerted by one wire on the other [per unit length] isKCET 2021 Medium
- A current of \(5 \mathrm{~A}\) is passing through a metallic wire of cross-sectional area \(4 \times 10^{-6} \mathrm{~m}^{2}\) If the density of charge carriers of the wire is \(5 \times 10^{26} \mathrm{~m}^{-3}\) the drift velocity of the electronswill beKCET 2007 Easy
- The total energy of an electron revolving in the second orbit of hydrogen atom isKCET 2018 Easy
- The current passing through the ideal ammeter in the circuit given below is
KCET 2007 Hard - A body is projected vertically upwards. The times corresponding to height while ascending and while descending are \(\mathrm{t}_{1}\) and \(\mathrm{t}_{2}\) respectively. Then the velocity of projection is ( is acceleration due to gravity)KCET 2008 Hard
- The amount of energy released when one microgram of matter is annihilated isKCET 2009 Easy
More PYQs from KCET
- Which of the following is false ?KCET 2008 Medium
- Two slabs are of the thicknesses \(d_{1}\) and \(d_{2}\). Their thermal conductivities are \(\mathrm{K}_{1}\) and \(\mathrm{K}_{2}\) respectively. They are in series. The free ends of the combination of these two slabs are kept at temperatures \(\theta_{1}\) and \(\theta_{2}\). Assume \(\theta_{1}>\theta_{2}\). The temperature \(\theta\) of their common junction isKCET 2010 Hard
- Rutherford's atomic model could account forKCET 2011 Easy
- A solid cylinder of radius \(R\) made of a material of thermal conductivity \(K_{1}\) is surrounded by a cylindrical shell of inner radius \(R\) and outer radius \(2 R\) made of a material of thermal conductivity \(K_{2}\).
The two ends of the combined system are maintained at two different temperatures. Then there is no loss of heat across the cylindrical surface and the system is in steady state. The effective thermal conductivity of the system isKCET 2013 Hard - The charge deposited on \(4 \mu \mathrm{F}\) capacitor in the circuit is
KCET 2009 Hard - The value of \(\int_{-\pi / 2}^{\pi / 2} \frac{\cos x}{1+e^{x}} d x\) isKCET 2020 Easy