When a ray of light passes through the center of curvature, it strikes the mirror perpendicularly, resulting in an angle of reflection of 0 degrees.

A ray of light passing through the optical center of a lens continues in a straight line without bending.

According to the law of reflection, the angle of reflection is equal to the angle of incidence, which is 30 degrees.

According to the law of reflection, the angle of reflection is equal to the angle of incidence. Therefore, the angle of reflection is 30 degrees.

Using Snell's law, n1 * sin(i) = n2 * sin(r). For air (n1=1) and water (n2=1.33), we find r = 45 degrees.

Power (P) is given by P = 1/f (in meters). Thus, P = 1/0.2 = +5 D.

Convex mirrors always produce virtual and erect images.

Using the lens formula 1/f = 1/v - 1/u, we find v = 20 cm.

For a concave lens, the image formed is virtual and erect when the object is placed in front of it.

Using the lens formula, the image is formed at 30 cm on the opposite side.

Using the lens formula 1/f = 1/v - 1/u, we find v = 33.33 cm.

Using the lens formula, 1/f = 1/v - 1/u, we find v = 30 cm, meaning the image is formed 30 cm on the opposite side.

Using the lens formula, 1/f = 1/v - 1/u. Here, f = 15 cm, u = -30 cm. Solving gives v = 10 cm.

Using the lens formula 1/f = 1/v - 1/u, we find v = 10 cm.

A concave lens always forms a virtual and erect image regardless of the object position.

When the object is at the focus of a concave mirror, the rays are parallel after reflection, resulting in no image being formed.

Using the grating equation d sin θ = nλ, where d = 1/500000 m, n = 1, and λ = 600 x 10^-9 m, we find θ ≈ 30 degrees.

The central maximum in a single-slit diffraction pattern is wider than all other maxima.

If the slit width is halved, the width of the central maximum increases because the angle for the first minimum increases.

The angular position of the first minimum is given by sin θ = λ/a.

Destructive interference occurs when the path difference is an odd multiple of λ/2 (i.e., (2n+1)λ/2).

Using the formula for minimum deviation, D = (n - 1)A. Here, n = √3 and A = 60 degrees. Thus, D = (√3 - 1) * 60 degrees, which approximates to 30 degrees.

Concave lenses always produce virtual and upright images.

Concave lenses always produce virtual and upright images.

Power (P) = 1/f = 1/(-0.15) = -6.67 D.

For a concave lens, the image formed is virtual and upright when the object is placed beyond the focal length.

The image formed by a concave lens is virtual and upright when the object is placed beyond the focal length.

The focal length (f) of a concave mirror is half the radius of curvature (R). Therefore, f = R/2 = 20 cm / 2 = 10 cm.

Power (P) is given by P = 1/f (in meters). Thus, P = 1/0.15 = +6.67 D.

Using the lens formula 1/f = 1/v - 1/u, we have 1/f = 1/40 - 1/(-60) = 1/40 + 1/60 = 1/24. Therefore, f = 24 cm.