# Ray Optics (NEET (NTA)-National Eligibility cum Entrance Test (Medical) Physics): Questions 82 - 86 of 105

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## Question number: 82

» Ray Optics » Lens Maker's Formula and Lens Formula

MCQ▾

### Question

An image is formed on the screen by a convex lens. When upper half part of lens is covered with black paper, then:

### Choices

Choice (4) Response

a.

Half image is formed

b.

Intensity of image will be enhanced

c.

Full image is formed

d.

None of the above

## Question number: 83

» Ray Optics » Power of a Lens

MCQ▾

### Question

If the focal length of a magnifier is 5 cm calculate the power of the lens.

### Choices

Choice (4) Response

a.

15 D

b.

20 D

c.

10 D

d.

5 D

## Question number: 84

» Ray Optics » Magnification

MCQ▾

### Question

A 0.5 cm high object is placed at 30 cm from a convex mirror whose focal length is 20 cm. Find the position and size of the image.

### Choices

Choice (4) Response

a.

6 cm, 0.5 cm

b.

12 cm, 0.2 cm

c.

5 cm, 0.1 cm

d.

18 cm, 0.2 cm

## Question number: 85

MCQ▾

### Question

An astronomical telescope has an angular magnification of magnitude 5 for distant objects. The separation between the objective and eye-piece is 36 cm and the final image is formed at infinity.

(1) The focal length of objective is 30 cm

(2) The focal length of objective is 25 cm

(3) The focal length of eye piece is 6 cm

(4) The focal length of eye piece is 12 cm

Select the correct answers and mark it according to the following codes:

Codes:

### Choices

Choice (4) Response

a.

1,2 and 3 are correct

b.

1 and 3 are correct

c.

1 and 2 are correct

d.

2 and 4 are correct

## Question number: 86

MCQ▾

### Question

At normal levels of intensities, the eye is most sensitive to

### Choices

Choice (4) Response

a.

Blue light

b.

Yellow light

c.

Red green light

d.

Red light