Reflection — Multiple Choice Questions

The co-ordinates of the point P(-3, 5) on reflection in the x -axis are :

1. (3, 5)

2. (-3, -5)

3. (3, -5)

4. (-3, 5)

Answer

We know that,

On reflection in x-axis :

The sign of y-coordinate changes and x-coordinate remains the same.

So, on reflection in x-axis coordinates of P(-3, 5) becomes (-3, -5).

Hence, option 2 is the correct option.

The reflection of the point P(-2, 3) in the y-axis is

1. (2, 3)

2. (2, -3)

3. (-2, -3)

4. (0, 3)

Answer

We know that,

Rule to find reflection of a point in y-axis :

1. Change the sign of abscissa i.e. x-coordinate.
2. Retain the ordinate i.e. y-coordinate.

∴ Coordinates of point P(-2, 3) on reflection in y-axis is (2, 3).

Hence, Option 1 is the correct option.

If the image of the point P under reflection in the x-axis is (-3, 2), then the coordinates of the point P are

1. (3, 2)

2. (-3, -2)

3. (3, -2)

4. (-3, 0)

Answer

Since, (-3, 2) is the image of the point P on reflection in x-axis so from graph P(-3, -2).

Hence, Option 2 is the correct option.

The reflection of the point P(1, -2) in the line y = -1 is

1. (-3, -2)

2. (1, -4)

3. (1, 4)

4. (1, 0)

Answer

We know that the reflection of the point (x, y) in the line y = a is the point (x, -y + 2a).

∴ The image of the point P(1, -2) under reflection in the line y = -1 is the point (1, -(-2) + 2 × (-1)) i.e the point (1, 0).

Hence, Option 4 is the correct option.

The reflection of the point A(4, -1) in the line x = 2 is

1. (0, -1)

2. (8, -1)

3. (0, 1)

4. none of these

Answer

We know that the reflection of the point (x, y) in the line x = a is the point (-x + 2a, y).

∴ The image of the point A(4, -1) under reflection in the line x = 2 is the point (-4 + 2 × 2, -1) i.e., the point P'(0, -1).

Hence, Option 1 is the correct option.

The reflection of the point (-3, 0) in the origin is the point

1. (0, -3)

2. (0, 3)

3. (3, 0)

4. none of these

Answer

We know that,

Rules to find the reflection of a point in the origin :

1. Change the sign of abscissa i.e. x-coordinate.
2. Change the sign of ordinate i.e. y-coordinate.

∴ Point (3, 0) is the image on reflection.

Hence, Option 3 is the correct option.

Which of the following points is invariant with respect to the line y = -2?

1. (3, 2)

2. (3, -2)

3. (2, 3)

4. (-2, 3)

Answer

Since, in (3, -2), y = -2, it means this point lies on the line. Hence, it a invariant point.

Hence, Option 2 is the correct option.