Question

While travelling by Delhi metro, you would have seen a big spherical mirror on the platform for safety. If the metro was 2.0m away from the mirror, its image was formed 5cm inside the mirror. Determine: (3) a) The type of mirror b) The focal length of the mirror c) The magnification of the image.

Answer 1

Given:

Big spherical mirror is present on the platform of metro station. When metro is 2 m away from the mirror, its image is formed 5cm inside the mirror.

To find:

• Type of mirror

• Focal length of mirror

• Magnification of image.

Calculation:

1. The mirror used in the platform is a convex mirror. This type of mirrors help passengers to stay alert when a metro train is approaching from behind.

2. Applying Mirror Formula :

$\therefore \: \dfrac{1}{f} = \dfrac{1}{v} + \dfrac{1}{u}$

$= > \: \dfrac{1}{f} = \dfrac{1}{5} + \dfrac{1}{( - 200)}$

$= > \: \dfrac{1}{f} = \dfrac{1}{5} - \dfrac{1}{200}$

$= > \: \dfrac{1}{f} = \dfrac{40 - 1}{200}$

$= > \: \dfrac{1}{f} = \dfrac{39}{200}$

$= > f = \dfrac{200}{39}$

$= > f = 5.12 \: cm$

So focal length of mirror is 5.12 cm.

3. Magnification can be calculated as follows;

$M = - \dfrac{v}{u}$

$= > M = - \dfrac{5}{( - 200)}$

$= > M = 0.025$

So , magnification is 0.025. That means that the image is erect and diminished.

Answer 2

Answer:Sorry could not tell for delhi but I will tell for mumbai

Explanation:

Planning. In February 2017, the MMRDA announced that the DMRC was preparing a detailed project report (DPR) on Line 9, a proposed 9 km extension of Metro 7 from Dahisar to Bhayander, via Mira Road. ... The project is estimated to cost ₹3,600 crore (US$500 million).

Termini: Dahisar East; Andheri (East)

Line length: 16.5 km (10.3 mi)

Locale: Mumbai Metropolitan Region

Status: Line 7 (Under Construction