An object located $100 \mathrm{~cm}$ from a concave mirror forms a real image $75 \mathrm{~cm}$ from the mirror. The mirror is then turned around so that its convex side faces the object. The mirror is moved so that the image is now $35 \mathrm{~cm}$ behind the mirror. How far was the mirror moved? Was it moved toward the object or away from the object?

A very long glass rod of $3.5-\mathrm{cm}$ diameter has one end ground to a convex spherical surface of radius $7.2 \mathrm{~cm}$. Its index of refraction is 1.5. (a) A point object in air is on the axis of the rod $35 \mathrm{~cm}$ from the surface. Find the image and state whether the image is real or virtual. Repeat $(b)$ for an object $6.5 \mathrm{~cm}$ from the surface and $(c)$ for an object very far from the surface. Draw a ray diagram for each case.

Check whether the statement is true or false. A convex mirror never forms a real image of a real object

Check whether the statement is true or false. A concave mirror always forms a virtual image.

Check whether the statement is true or false. The virtual image formed by a concave mirror is always smaller than the object

A concave mirror has a radius of curvature $6 \mathrm{~cm}$. Draw rays parallel to the axis at $0.5 \mathrm{~cm}, 1 \mathrm{~cm}, 2 \mathrm{~cm}$, and $4 \mathrm{~cm}$ above the axis, and find the points at which the reflected rays cross the axis. (Use a compass to draw the mirror and a protractor to find the angle of reflection for each ray.) $(a)$ What is the spread $\delta x$ of the points where these rays cross the axis? (b) By what percentage could this spread be reduced if the edge of the mirror were blocked off so that parallel rays more than $2 \mathrm{~cm}$ from the axis could not strike the mirror?

In an effort to be more environmentally conscious, a homeowner may upgrade a furnace that runs on fuel oil to a natural gas unit. The investment will be $2500 installed. The cost of the natural gas will average$60 per month over the year, instead of the $145 per month that the fuel oil costs. Assume energy costs increase 3% per year. If the interest rate is 9% per year, how long will it take to recover the initial investment?

A concave spherical mirror has a radius of curvature of $6 \mathrm{~cm}$. A point object is on the axis $9 \mathrm{~cm}$ from the mirror. Construct a precise ray diagram showing rays from the object that make angles of $5^{\circ}, 10^{\circ}, 30^{\circ}$, and $60^{\circ}$ with the axis, which strike the mirror and are reflected back across the axis. (Use a compass to draw the mirror, and use a protractor to measure the angles needed to find the reflected rays.) What is the spread $\delta x$ of the points where these rays cross the axis?

Light with wavelength 442 nm passes through a double-slit system that has a slit separation d = 0.400 mm. Determine how far away a screen must be placed so that dark fringes appear directly opposite both slits, with only one bright fringe between them.

A certain telescope uses a concave spherical mirror that has a radius equal to 8.0 m. Find the location and diameter of the image of the moon formed by this mirror. The moon has a diameter of $3.5 \times 10^6 \mathrm{~m}$ and is $3.8 \times 10^8 \mathrm{~m}$ from Earth.

A 1500-kg car traveling at $100 \mathrm{~km} / \mathrm{h}$ crashes into a concrete wall. If the temperature of the air is $20^{\circ} \mathrm{C}$, calculate the entropy change of the universe.

Convex mirrors are used in many stores to provide a wide angle of surveillance for a reasonable mirror size. Your summer job is at a local convenience store that uses the mirror.. This setup allows you (or the clerk) to survey the entire store when you are 5.0 m from the mirror. The mirror has a radius of curvature equal to 1.2 m. Assume all rays are paraxial.

If the customer is 2.0 m tall, how tall is his image?

Convex mirrors are used in many stores to provide a wide angle of surveillance for a reasonable mirror size. Your summer job is at a local convenience store that uses the mirror.. This setup allows you (or the clerk) to survey the entire store when you are 5.0 m from the mirror. The mirror has a radius of curvature equal to 1.2 m. Assume all rays are paraxial.

Is the image in front of or behind the mirror?

Convex mirrors are used in many stores to provide a wide angle of surveillance for a reasonable mirror size. Your summer job is at a local convenience store that uses the mirror.. This setup allows you (or the clerk) to survey the entire store when you are 5.0 m from the mirror. The mirror has a radius of curvature equal to 1.2 m. Assume all rays are paraxial.

If a customer is 10 m from the mirror, how far from the mirror is his image?