An object is placed 15 cm in front of a convex lens of focal length 10 cm. Find the nature and position of the image formed. Where should a concave mirror of radius of curvature 20 cm be placed so that the final image is formed at the position of the object itself?
CBSE OUTSIDE DELHI - SET 1 PANCHKULA 2015
Download our app for free and get startedPlay store
For lens $\frac{1}{\text{v}} - \frac{1}{\text{u}} = \frac{1}{\text{f}}$
$\frac{1}{\text{v}} - \frac{1}{-15} = \frac{1}{+10}$
$\frac{1}{\text{v}} + \frac{1}{15} = \frac{1}{10}$
$\therefore\text{v} = 30\text{cm}$
Nature of image- real, magnified
Final image formed will be at the object itself only if image formed by lens is at the position of centre of curvature of mirror.
$\therefore\text{D} = (30 + \text{R})\text{cm} =(30 +20)\text{cm} = 50 \text{cm}.$
(Distance of mirror from lens).
art

Download our app
and get started for free

Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*

Similar Questions

  • 1
    A bulb rated 60W at 220V is connected across a household supply of alternating voltage of 220V. Calculate the maximum instantaneous current through the filament.
    View Solution
  • 2
    Draw a circuit diagram of a C.E. transistor amplifier. Briefly, explain its working and write the expression for (i) current gain, (ii) voltage gain of the amplifier.
    View Solution
  • 3
    The instantaneous current in an ac circuit is $\text{i}=0.5\sin314\text{t},$ what is (i) rms value and (ii) frequency of the current.
    View Solution
  • 4
    A voltage $V = V_o$ sin $\omega\text{t}$ is applied to a series LCR circuit. Derive the expression for the average power dissipated over a cycle. Under what condition is (i) no power dissipated even though the current flows through the circuit, (ii) maximum power dissipated in the circuit?
    View Solution
  • 5
    When an inductor L and a resistor R in series are connected across a 12 V, 50 Hz supply, a current of 0.5 A flows in the circuit. The current differs in phase from applied voltage by $\pi/3$ radian. Calculate the value of R.
    View Solution
  • 6
    A resistor R and an inductor L are connected in series to a source $\text{V}=\text{V}_0\sin\omega\text{t}.$
    Find:
    1. Peak value of the voltage drops across R and across L,
    2. Phase difference between the applied voltage and current. Which of them is ahead?
    View Solution
  • 7
    Answer the following:
    1. In what way is diffraction from each slit related to the interference pattern in a double slit experiment?
    2. When a tiny circular obstacle is placed in the path of light from a distant source, a bright spot is seen at the centre of the shadow of the obstacle. Explain, why.
    3. How does the resolving power of a microscope depend on (i) the wavelength of the light used and (ii) the medium used between the object and the objective lens?
    View Solution
  • 8
    1. Mention two properties of soft iron due to which it is preferred for making an electromagnet.
    2. State Gauss's law in magnetism. How is it different from Gauss's law in electrostatics and why?
    View Solution
  • 9
    State Biot – Savart law. Deduce the expression for the magnetic field at a point on the axis of a current carrying circular loop of radius ‘R’, distant ‘x’ from the centre. Hence write the magnetic field at the centre of a loop.
    View Solution
  • 10
    1. What is total internal reflection? Under what conditions does it occur?
    2. Find a relation between critical angle and refractive index.
    3. Name one phenomenon which is based on total internal reflection.
    View Solution