SCIENCE 2nd Quarter Exam Reviewer PDF

**SCIENCE** **2ND Quarter Exam Reviewer** **ELECTRICITY AND MAGNETISM** 1819- Hans Christian Oersted discovered that a current carrying wire caused a nearby magnetized compass needle to deflect. Magnetic poles- magnetic south or north Magnetism- property of being able to attract objects **ELEC...

**SCIENCE** **2ND Quarter Exam Reviewer** **ELECTRICITY AND MAGNETISM** 1819- Hans Christian Oersted discovered that a current carrying wire caused a nearby magnetized compass needle to deflect. Magnetic poles- magnetic south or north Magnetism- property of being able to attract objects **ELECTROMAGNETIC WAVE THEORY** Accelerating charges causes a changing Electrical Field and Magnetic Field, producing **ELECTROMAGNETIC WAVES** can travel in material medium and in vacuum (free space) All EM waves have the same speed (the speed of light) **Wavelength is inversely proportional to the frequency. As wavelength decreases, the frequency of the wave increases.** **ELECTROMAGNETIC SPECTRUM** \- continuum of electromagnetic waves arranged according to frequency and wavelength. Lowest frequency to highest Radiowaves, Microwaves, Infrared, Visible Light, Ultraviolet, X-rays, Gamma rays **1. RADIO WAVES** \- longest wavelength \- discovered by Heinrich Hertz 1887 \- produced by alternating current Wavebands- smaller region of radio waves RADAR- Radio detection and ranging MRI- Magnetic source imaging GPS- Global positioning system RFID- Radio frequency identification LIDAR- Light detection and ranging **APPLICATIONS:** Automatic doors, WiFi, Bluetooth, GPS, RFID **2. MICROWAVES** -discovered by James Clerk Maxwell 1864 \- 300 MHz to 300 GHz **APPLICATIONS:** **3. INFRARED** -discovered by William Herschel 1800 \- literally mean below red \- higher temperatures produce shorter infrared waves **APPLICATIONS:** remote control, burglar alarm systems, night vision camera, thermometers, Infrared induction, Medical infrared imaging, surveillance camera **4. VISIBLE LIGHT** \- only EM wave that can be seen by our naked eye **APPLICATION**: It helps us see objects, traffic lights, commercial displays, car headlights, television, liquid crystal display (**LCD),** used by plants in photosynthesis **LASER**- Light amplification by stimulated emission of radiation **5. ULTRAVIOLET RADIATION** -discovered by John Wilhelm Ritter \- major source is sun UVA, UVB, UVC UVA- used to treat skin conditions like psoriasis and vitiligo UV- stimulates the production of vitamin D **6. X-RAYS** -sometimes called roentgen rays \- discovered by Wilhelm Conrad Roentgen -produced by the sun and other stars -classified as either soft or hard **APPLICATIONS:** detect abnormalities in the skeletal system, dental imaging, Computer axial tomography (CAT), airport security checks, diffraction **7. GAMMA RAYS** \- discovered by Paul Villard 1900 \- astronomical objects, including the sun , clouds of interstellar matter, and remnants of supernovae **APPLICATIONS:** detect cracks in metals, food irradiation, Radiotherapy **External radiotherapy-** the patient is exposed to a beam of radiation **EFFECTS OF VISIBLE LIGHT:** 1\. Visible light powers the photosynthetic cycle of a plant 2\. Lack of sunlight can lead to depression and brain damage 3\. Can cause photodegradiation of pigments and colorants. 4\. Sunlight can cause breakdown of the object's molecular structure 5\. Age-related macular degeneration **EFFECTS OF INFRARED:** 1\. Exposure to infrared radiation for long periods may experience eye damage 2\. Can damage skin and tissues 3\. Involved in the greenhouse effect 4\. Elevated temperatures and changes in weather **EFFECTS OF ULTRAVIOLET LIGHT (UV)** 1\. Overexposure to uv radiation may cause skin cancer 2\. Damage of the eye 3\. Suppression of immune system 4\. Harmful UV rays cause reduction in the growth rate of photosynthesis **EFFECTS OF XRAY** 1\. The radiation from xrays can harm living cells 2\. Cataracts in the eyes 3\. Skin burns **EFFECTS OF GAMMA RAYS:** 1\. Can kill living cells 2\. May be develop mil case of radiation poisoning 3\. Risk of cancer **MODULE 3: MIRRORS AND LENSES** **REFLECTION-** bouncing off of light rays **RAYS OF LIGHT:** **Incident Ray-** ray of light approaching the mirror **Reflected ray**- ray of light which leaves the mirror **Normal line**- ray strikes the mirror **Types of reflection:** **Specular/ Regular**- reflection on smooth surfaces **Diffused/ Irregular**- on rough surfaces **Spherical mirrors / Curved mirror**- is a reflecting surface in which its surface is a section of sphere **2 TYPES OF SPHERICAL MIRROR** **Convex mirror**- diverging mirror; reflective surface bulges towards the light source **Center of curvature ( c)** center of sphere **Radius ( r)** - distance from the mirror **Vertex (v)-** center of the mirror **Focal point/ focus (f)**- point between the center of c and v **LENS**- transparent material made of glass or plastic **TYPES OF LENSES** **CONVEX LENS-** thicker (center); thinner (edges); forms real and virtual **REAL IMAGES**- images formed on screen after reflection **VIRTUAL IMAGES**- formed by intersection of non-real rays **IMAGE FORMATION** 1. If an object is placed between the focal point and the pole of a concave mirror, **A VIRTUAL, UPRIGHT, AND MAGNIFIED IMAGE IS FORMED.** 2. If an object is placed at the center of curvature of a concave mirror, **A REAL, INVERTED, AND SAME-SIZED IMAGE** is formed at the center of curvature itself. 3. As the angle between the mirrors increases from 90° to 120°, the number of images **DECREASES**. 4. If a light ray traveling parallel to the axis of a convex lens, strikes the lens: **IT TRAVELS TO THE AXIS PASSING THROUGH ITS FOCAL POINT.** 5. When an object is placed between the focus and the mirror of a concave mirror: **AN ERECTED, A VIRTUAL, AND MAGNIFIED IMAGE IS FORMED.** **FACTS ABOUT CONCAVE MIRROR** 1. Concave mirrors can form both real and virtual images, depending on the object\'s position. An inverted image is formed when the object is placed beyond the focal point. 2. An object placed between the focus (f) and the pole (p) of a concave mirror will form a virtual and magnified image. 3. **An object placed at the center of curvature of a concave mirror will form an image of the same size as the object.** This image will be real and inverted 4. If an object is placed between a concave mirror and its focal point. **A virtual, erected, and magnified image is formed.** 5. **Dentists typically use a concave mirror.** A concave mirror can produce magnified images when the object (your teeth) is placed within its focal length. this allows the dentist to examine your teeth in detail. **FACTS ABOUT CONVEX MIRROR** 1. A convex mirror is commonly used by department stores **to give a wider view of the store and a smaller image of shoppers.** 2. Convex mirror is used in side mirror **to give a wider field of view by reducing the size of objects.** 3. **A microscope uses two convex lenses to magnify small objects. The objective lens and the eyepiece lens work together to produce a highly magnified image** **MAGNET PROPERTIES** 1. **All three factors can affect the electromotive force (emf) induced in the coil in a magnet.** 2. The role of the coil in generating electricity when a magnet moves through it? 3. To increase the amount of electricity generated when moving a magnet through a coil, you can consider the following factors: **GENERATOR** **In an improvised generator, the primary transformation is from mechanical energy to electrical energy.**    **ELECTRIC MOTOR** How does an electric motor convert electrical energy into mechanical energy? **By causing a coil to rotate in a magnetic field, producing motion.** What is the main principle behind the operation of an electric motor? **The interaction between electric current and a magnetic field.**