# Directivity Online Exam Quiz

Directivity GK Quiz. Question and Answers related to Directivity. MCQ (Multiple Choice Questions with answers about Directivity

### Effective aperture is the ability of antenna to extract energy from the electromagnetic wave.

**Options**

A : TRUE

B : FALSE

C : -

D : -

### Expression for aperture efficiency in terms of physical aperture Ae and effective aperture Aem is __

**Options**

A : \frac{A_e}{A_{em}}

B : \frac{A_{em}}{A_e}

C : \frac{A_e+A_{em}}{A_e-A_{em}}

D : \frac{A_e-A_{em}}{A_e+A_{em}}

### If physical aperture of antenna is 0.02m2 and aperture efficiency is 0.5, then what is the value of effective aperture?

**Options**

A : 0.0004m2

B : 0.001m2

C : 0.01m2

D : 25m2

### What is the directivity of antenna having effective aperture 1 m2?

**Options**

A : \frac{4\pi}{\lambda^2}

B : \frac{\lambda^2}{4\pi}

C : 1

D : 4?

### What is the effective aperture of a Half-wave dipole operating at 100MHz?

**Options**

A : 1.07m2

B : 1.17m2

C : 1.27m2

D : 1.77m2

### What is the effective aperture of Hertzian dipole antenna operating at frequency 100 MHz?

**Options**

A : 1.07m2

B : 0.17m2

C : 1.7m2

D : 1.2m2

### What is the relation between effective length and Effective aperture of antenna?

**Options**

A : A_e = \frac{dL^2\eta}{4R_{rad}}

B : A_e = \frac{dL^2}{4\eta R_{rad}}

C : A_e = \frac{dL^2 R_{rad}}{4\eta}

D : A_e = \frac{dL^2 \eta ^2}{4R_{rad}}

### Which of the following best describes the condition for Maximum effective aperture?

**Options**

A : Load impedance must be equal to the antenna impedance

B : Load impedance must be equal complex conjugate to the antenna impedance

C : Receiver power should be minimum

D : Transmitter power should be minimum