An object is located 30.0 cm from a concave mirror. The focal length is 15.0 cm. What is the image distance?

Use the equation [tex]d_i = \frac{d_0 f}{d_0 - f}[/tex].

A. -10.0 cm

B. -30.0 cm

C. 10.0 cm

D. 30.0 cm



Answer :

To find the image distance for an object placed in front of a concave mirror, we use the mirror equation:

[tex]\[ d_i = \frac{d_0 f}{d_0 - f} \][/tex]

where:
- [tex]\( d_0 \)[/tex] is the object distance,
- [tex]\( f \)[/tex] is the focal length,
- [tex]\( d_i \)[/tex] is the image distance.

Given values:
- [tex]\( d_0 = 30.0 \, \text{cm} \)[/tex],
- [tex]\( f = 15.0 \, \text{cm} \)[/tex].

Substitute these values into the mirror equation:

[tex]\[ d_i = \frac{30.0 \, \text{cm} \times 15.0 \, \text{cm}}{30.0 \, \text{cm} - 15.0 \, \text{cm}} \][/tex]

Calculate the numerator:

[tex]\[ 30.0 \, \text{cm} \times 15.0 \, \text{cm} = 450.0 \, \text{cm}^2 \][/tex]

Calculate the denominator:

[tex]\[ 30.0 \, \text{cm} - 15.0 \, \text{cm} = 15.0 \, \text{cm} \][/tex]

Now, divide the numerator by the denominator to find the image distance:

[tex]\[ d_i = \frac{450.0 \, \text{cm}^2}{15.0 \, \text{cm}} = 30.0 \, \text{cm} \][/tex]

Therefore, the image distance [tex]\( d_i \)[/tex] is:

[tex]\[ d_i = 30.0 \, \text{cm} \][/tex]

So, the correct answer is:

D. [tex]\( 30.0 \, \text{cm} \)[/tex]