A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
A radio can tune to minimum frequency, \(ν_1 = 7.5 \ MHz= 7.5 × 10^6 Hz \)
Maximum frequency, \(ν_2 = 12\ MHz = 12 × 10^6 Hz \)
Speed of light, \(c = 3 × 10^8 \ m/s \)
Corresponding wavelength for \(ν_1\) can be calculated as:
\(λ_1 = \frac {c}{v_1}\)
\(λ_1 = \frac {3\times 10^8}{7.5\times 10^6 }= 40 \ m\)
Corresponding wavelength for \(ν_2\) can be calculated as:
\(λ_2 = \frac {c}{v_2}\)
\(λ_2 = \frac {3\times 10^8}{12\times 10^6 }= 25 \ m\)
Thus, the wavelength band of the radio is \(40 \ m\) to \(25 \ m\).
A racing track is built around an elliptical ground whose equation is given by \[ 9x^2 + 16y^2 = 144 \] The width of the track is \(3\) m as shown. Based on the given information answer the following: 
(i) Express \(y\) as a function of \(x\) from the given equation of ellipse.
(ii) Integrate the function obtained in (i) with respect to \(x\).
(iii)(a) Find the area of the region enclosed within the elliptical ground excluding the track using integration.
OR
(iii)(b) Write the coordinates of the points \(P\) and \(Q\) where the outer edge of the track cuts \(x\)-axis and \(y\)-axis in first quadrant and find the area of triangle formed by points \(P,O,Q\).
The term used by scientists to describe the entire range of light that exists is the electrostatic spectrum. Light is a wave of alternating electric and magnetic fields. The propagation of light doesn't vary from waves crossing an ocean. Like any other wave, light also has a few fundamental properties that describe it. One is its frequency. The frequency is measured in Hz, which counts the number of waves that pass by a point in one second.
The electromagnetic waves that your eyes detect are visible light and oscillate between 400 and 790 terahertz (THz). That’s several hundred trillion times a second.