Images Formed by Mirrors · 镜子形成的像
Your reflection stands behind the glass — but nothing is there
- Look in a bathroom mirror and "you" appear to stand an equal distance behind it.
- Reach behind the mirror and there's nothing — the image is virtual.
- Mirrors form images by bouncing rays according to the law of reflection.
- Curved mirrors can shrink, enlarge or even flip the image.
你的镜像站在玻璃后面——可那里什么也没有
- 照浴室的镜子,"你"看起来站在镜子后面等距离的地方。
- 伸手到镜子后面,什么也没有——这个像是虚的。
- 镜子按反射定律弹回光线来成像。
- 曲面镜能缩小、放大甚至翻转这个像。
Plane (flat) mirror images
- A plane mirror makes a virtual, upright image the same size as the object.
- The image sits as far behind the mirror as the object is in front.
- It appears left-right reversed, but is otherwise identical.
- "Virtual" means the rays only appear to come from behind — no light is really there.
平面镜成的像
- 平面镜成一个虚的、正立的、与物体等大的像。
- 像位于镜子后面,与物体在前面的距离相等。
- 它看起来左右反转,但其余完全相同。
- "虚"意味着光线只是看起来从后面来——那里其实没有光。
Trace the image rays · 追踪成像光线
Move the object and focal length and watch how the image position and size change. · 移动物体和焦距，观察像的位置和大小如何变化。
You stand $0.5\ \text{m}$ in front of a flat mirror. How far behind the mirror is your image, in metres? · 你站在平面镜前$0.5\ \text{m}$处。你的像在镜后多远，单位为米？
A plane mirror puts the image as far behind as the object is in front: $0.5\ \text{m}$. · 平面镜将像置于镜后，距离等于物距：$0.5\ \text{m}$。
A plane mirror image is: · 平面镜成的像是：
It is virtual, upright and the same size as the object. · 它是虚像、正立且与物体等大。
Curved mirrors
- A concave (curved-in) mirror can focus rays to a point — it can magnify or flip.
- Close up it gives an enlarged upright image (a shaving/make-up mirror); far off, a small inverted one.
- A convex (curved-out) mirror always gives a small, upright, virtual image with a wide view.
- That is why convex mirrors are used as car and shop security mirrors.
曲面镜
- 凹(向内弯)面镜能把光线聚到一点——它能放大或翻转。
- 近处它给出放大的正立像(剃须/化妆镜);远处则是小的倒立像。
- 凸(向外弯)面镜总是给出小的、正立的虚像,视野宽阔。
- 这就是为什么凸面镜被用作汽车和商店的监视镜。
A ____ mirror gives a small, upright image with a wide view, used for security mirrors. · ____镜产生小尺寸、正立的图像且具有宽广视野，用于安全镜。
Convex mirrors always give a small, wide-view virtual image. · 凸面镜总是产生小尺寸、宽视野的虚像。
Select all · 所有 correct statements about mirrors. · 选择关于镜子的所有正确陈述。
Plane = virtual same-size; concave can make real inverted images; convex widens the view. Plane mirrors do not magnify. · 平面镜=虚像等大；凹面镜可产生实像倒立像；凸面镜扩大视野。平面镜不放大。
Real vs virtual images
- A real image forms where rays actually cross — you can catch it on a screen.
- A virtual image forms where rays only appear to come from — it can't be projected.
- Plane and convex mirrors make only virtual images.
- Concave mirrors make a real image when the object is beyond the focal point.
实像 vs 虚像
- 实像在光线真正相交处形成——你能用屏幕接住它。
- 虚像在光线只看起来来自的地方形成——它无法被投射。
- 平面镜和凸面镜只成虚像。
- 当物体在焦点之外时,凹面镜成实像。
Which type of image can be projected onto a screen? · 哪种类型的像可以投射到屏幕上？
A real image forms where rays actually cross, so it can be caught on a screen. · 实像是在光线实际相交处形成的，因此可以被屏幕接收。
A plane mirror image is virtual — there is no light behind the mirror. It is not magnified: the image is exactly the same size as the object, just reversed left-to-right and placed an equal distance behind.
平面镜的像是虚的——镜子后面没有光。它没有被放大:像与物体完全等大,只是左右反转并放在等距离的后方。
A plane mirror magnifies the image, making it larger than the object. · 平面镜放大图像，使其比物体大。
A plane mirror image is exactly the same size as the object. · 平面镜成的像与物体大小完全相同。
You stand $0.5\ \text{m}$ in front of a flat mirror. Where is your image, and how big?
- The image is $0.5\ \text{m}$ behind the mirror — so it looks $1.0\ \text{m}$ away from you.
- It is upright and the same size as you.
你站在一面平面镜前 $0.5\ \text{m}$ 处。你的像在哪里,有多大?
- 像在镜后 $0.5\ \text{m}$——所以它看起来离你 $1.0\ \text{m}$。
- 它正立,且与你等大。
A plane mirror forms a virtual, upright image the same size as the object, as far behind as the object is in front. Concave mirrors can make magnified or real (inverted) images; convex mirrors always give a small, wide-view virtual image. Real images can be projected; virtual ones cannot.
平面镜成一个虚的、正立的、与物体等大的像,在镜后与物体在镜前等距离处。凹面镜能成放大的或实(倒立)的像;凸面镜总是给出小的、宽视野的虚像。实像能被投射;虚像不能。