Question : Behind the cornea, there is a dark muscular structure called the ______.

Option 1: Retina

Option 2: Pupil

Option 3: Iris

Option 4: Lens

Question : Dioptre is the unit of:

Option 1: power of a lens

Option 2: focal length of a lens

Option 3: light intensity

Option 4: sound intensity

Question : If $\sin A+\sin ^2 A=1$, then the value of the expression $\left(\cos ^2 A+\cos ^4 A\right)$ is

Option 1: $\frac{3}{2}$

Option 2: $1$

Option 3: $2$

Option 4: $\frac{1}{2}$

Question : The given expression is equal to $\frac{\sin^4 A+\cos^4 A}{1-2 \sin^2 A \cos^2 A}$:

Option 1: 1

Option 2: –1

Option 3: 0

Option 4: 2

Question : Find the value of the following expression $2(\tan ^2 A \cos ^2 A+\cos ^2 A)$.

Option 1: 4

Option 2: 1

Option 3: 3

Option 4: 2

Question : If $ a^{2}+a+1=0$, then the value of $a^{5}+a^{4}+1$ is:

Option 1: $a^2$

Option 2: $1$

Option 3: $0$

Option 4: $a+1$