Question Discussion & Solution

• The Best example of Run time polymorphism is Function Overriding
• Function Overloading is the example of Compile time polymorphism
• Protected is an Access modifier  

Important Point

Compile-time polymorphism

It means binding is occurring at compile time It can be achieved through static binding. If a class has multiple methods having the same name but different in parameters, it is known as Method Overloading.

Run time polymorphism

At run time we came to know which method is going to invoke It can be achieved through dynamic binding. If subclass (child class) has the same method as declared in the parent class, it is known as method overriding

Access Modifiers

It specifies the accessibility or scope of a field, method, constructor, or class. There are three types of Access modifiers

• Public: The methods or data members that are declared as public can be accessed anywhere in the program.
• Private:  The methods or data members declared as private are accessible only within the class in which they are declared.
• Protected: The methods or data members declared as protected can accessible within the same class or class which is inherited from it.

The correct answer is 8 minutes.

• It takes 8 minutes to reach the earth.

Key Points

• Light is a form of energy which is propagated as electromagnetic waves.
• In the spectrum of electromagnetic waves, it lies between the ultra-violet and infra-red region and has a wavelength between 3900 Å to 7800 Å.
• light behaves as wave and particle both. 
• Speed of light is maximum in vacuum and air (3×10⁸ m/s).
• It is a transverse wave.
• It takes 8 min 19 s to reach on the earth from the sun.
• The light reflected from the moon takes 1.28 s  to reach earth.

Additional Information

• Electromagnetic waves are transverse, hence light is a transverse wave.
• Wave nature of light explains rectilinear propagation, reflection, refraction, interference, diffraction and polarization of light. 
• Refractive Index of a medium is defined as the ratio of the speed of light in a vacuum to the speed of light in the medium. 
• Light is measured with two main alternative sets of units: radiometry consists of measurements of light power at all wavelengths, while photometry measures light with a wavelength.

Mammalogist is a person who studies about mammals. Similarly,

The correct answer is DPI (dots per inch).

• The resolution of a printer is measured in DPI.

​Key Points

Explanation:

• Sound is a longitudinal mechanical wave that propagates by making compressions (high pressure) and rarefactions(low pressure) in its propagating medium. 

• The amplitude of wavelength is the maximum distance the particle oscillating moves from the mean position.
• The frequency of the wave is the number of times one complete cycle of compressions 

• More the frequency more is the pitch of the sound, the sound is having more shrillness. 
• The more the amplitude the more is the loudness of the sound. 

So, loudness depends upon the amplitude.

Important Points 

• The Pitch of the sound depends upon frequency. 
• Mathematically, loudness is directly proportional to the square of the amplitude. 

L ∝ A2