Science Prep 3 Revision on unit 2 part 1 Second term 2025 2026

revision on unit two first part by the end of this lesson or unit students will be able to number one identify the phenomenon radio activity number two identify the electric resistance current intensity and the potential difference. Number three, identify the methods of connecting the cells in electric circuits series connection and par connection. first question complete number one. Space is the charge transferred by constant current of 1 ampere in 1 second. Column is the charge transfer by constant current of 1 ampere in 1 second. Number two, when the quantity of electricity is doubled and the time of its passing decrease to its hub, the current intensity will increase four times. Number application, number of application, assumed number of quantity of electricity and number of time. Okay. And calculate the current intensity and change the quantity electricity to double and change the time to decrease to its half. Okay. And the new current intensity. Okay. will equal increase four times. And when increasing the busing time of electricity to double and the amount of electricity remained constant. The current intensity will decrease to half will decrease to half application. Okay, we now calculate the current intensity. Number three, the measuring unit of the electric current intensity is ampere. Number four, the opposition that the electric current faces during the passage through conductor is space. The position that the electric current faces during the passage through conductor is electric resistance. Number five, space is used to change the electric resistance in an electric circuit. Space is used to change the electric resistance in an electric circuit. Reate is used to change the electric resistance in an electric circuit. Number six. Juul bear column is the measuring unit of jewel bear column is the measuring unit of potential difference. Jewel measuring unit torque and column is the measuring unit of amount of current charge equal potential difference while jewel per column dot ampere is the measuring unit of space. Jewel measuring unit of column of work. Column is the measuring unit of amount of charge. measuring unit of current intensity. Jewel per column or divided equal volt equal. measuring unit of electric resistance. Number seven, the space is used to measure the electric resistance. The space is used to measure the electric resistance. Ohm meter. The ohm meter is used to measure the electric resistance. number eight, the space is used to measure the electromoted force of battery in units known as space. The voltmeter is used to measure the electromotive force of battery in units known as volts. Number nine, column per second is measuring unit of column. Measuring unit of amount of charge. Second measuring unit of time amount of charge divided time equal current intensity. Okay. Equal ampere column per second equal ampere is the measuring unit of the of current intensity. Number 10. The voltometer is connected in space between the pools of dry cells or battery to measure the electromotive force of battery. The voltmeter is connected in parallel or series in parallel between the BS of dry cells of battery to measure the electromotive force of battery when the electric circuit is is opened. Okay. Number 11. Transmission of electric charge depends on the space between two conductors and it does not depend on space. Transmission of electric charge depends on the potential difference between two conductors and it does not depend on quantity of charge. Another question choose number one. The radio activity phenomenon was discovered by the scientists letter let Borel letter and bear vault the radioact was discovered by the scientist which Number two, cosmic radiation is from space sources of radiation pollution. Letter natural. Letter artificial. Letter industrial. Letter no correct answer. Cosmic radiation is from natural sources of radiation pollution which number three public should not be exposed to radiation in amounts more than space mainly severed per year. Public should not be exposed to radiation in amounts more than space millise per year. Letter 1, letter 5, letter 15. Letter 20. Public shouldn't be exposed to radiation in amounts more than one mainly severed per year. Number four, base is non radioactive element. Base is non-radioactive element. Letter radium. Letter uranium. Letter zirconium. Letter magnesium. Magnesium is non radioactive element. Number five, direct current can be produced from letter electrochemical cells, letter electric generators, letter electric power stations, letter electric motors, direct Current can be produced from electro chemical cells. Letter Number six. The alternating current is used in space. Letter electrolyes process. Letter lighting houses. Letter electroplating process. Letter both and The alternating current is used in lighting houses which in number seven on connecting on connecting five electric cells the electromotive force of each one is 2 volt in par. The total electromotive force of the new battery equal space volt connecting five electric cells. The electromotive force of H1 H2 volt in parallel in par. The total electromotive force equal electromotive force of one of them. Okay. And the total electromotive force of the new battery equals 2 volt. Another question. Choose the old words. Number one. An electric current of constant intensity and direction or can be transferred for long distance or produced from dry cell or used in electroplating. can be transferred for long distances. Can be transferred for long distance that alternate alternating current. Okay. Number two, ultimeter dry cell or battery or electric generator. Ult dry cell battery electric generator. Volton meter dry cell battery electric generator sources of electric current while voltonator measure potential difference and electromotive force of dry cell or battery. Number three, alternating electric current or direct electric current or used in electroplating or can be transferred for short distance. Alternating electric current used in electrol direct electric current can be transferred for short distance direct electric current. Another question. What happen when number one group of similar electric cells are connected in series related to electromotive force. Group of similar electric cells are connected in series related to electromotive force. The total electromotive force will increase or decreases equal times one where number of electric cells. Question number two, group of similar electric cells are connected in par related to electrootive force. group of similar electric cells are connected in parallel related to electrootive force. The total electromotive force decreases equal electromotive force of one object. Question number three. quantity of charge. Quantity of charge that passes through cross-section of conductor in 1 second increases. Quantity of charge that pass through cross-section of conductor in 1 second increases. relation between current intensity and quantity of charge or amount of charge directly proportional. Okay. When quantity of charge that pass through cross-section of conductor in one second increases the electric current intensity will increase relationship directly. Okay. Another question. Give reasons for number one. The voltometer is connected across the two pools of battery. The voltometer is connected across the two pools of battery to measure the electromotive force of the battery. Number two, when two conductors have the same potential difference or connected, no electric current bus passes when two conductors have the same potential or connected. No electric current bus same potential like 50 and 50. Okay. potential difference in equal zero because there is no potential difference between the potential difference in could equally equal zero because it has the same or they have the same potential are connected together so no electric current bus number three the sliding state variable resistance is used in some electric sliding state or variable resistance is used in some electric circuit. The importance of sliding restate to control the current intensity passing through the circuit and the potential difference in the different parts of the circuit. Control the current intensity. Okay. passing through the circuit and the potential difference in the different parts of the circuit. Question number four, the reset controls the current intensity flowing through the electric circuit. The restor controls the current intensity flowing through the electric circuit because if we increase the length of the wire the resistance increase and the current intensity decreases and vice vers. So we increase the length of the wire the resistance increases and the current intensity decreases and vice versa. Question number five. Some electric cells are connected in both series and par to obtain battery with different electromotive force values. Question number six. Some electric cells are connected in series in the electric circuits. When we connect the electric cells in series to obtain battery with high electromotive force with the total electromotive force is the sum or summation of the individual cells. Question number seven. Some electric cells are connected in par in the electric circuits to obtain battery with low electromotive force because the total electromotive force is equal to the electromotive force of single cell. But it increases the batteries capacity life or life. Okay. Question number eight. Uranium element is considered as radioactive element. Uranium element is considered as radioactive element because its atoms nuclei contain number of neutrons more than required for its stability which lead to presence of exist energy that release as invisible. radiation. Question number nine, the atoms nuclei of radioactive elements is unstable due to their exist energy because the number of neutrons in its atoms nuclei is more than required for its stability. problems. Problem number one in the following figure. Number one, calculate the ammeter reading. Number two, calculate the value of the work done to transfer charge of 100 column. Solution E= series electromotive force of serious dry cells plus electromotive force of group of bar connection of dry cells equal 3 + 3 + 4 = 3 + three plus four. The two dry cells connected in parallel equal one of single cell 3 + 3 + 4 equal 10 volt. Current intensity equal potential difference will be divided Resistance electric resistance are equal divided 4 equal 2.5 ampere work equal potential difference times the amount of charge equal 10 * 100 equal 1,00 000 joule. Okay. Problem number two. Equates the work done to transfer an electric charge of 100 column through conductor if the potential difference between its terminals or ends is 240 volt. Work done equal potential difference times the amount of electric charge equal 100 * equal 24,000 jew. Problem number three. If the work done to transfer an electric charge of 200 column between two points is 44,000 joule. Calculate the potential difference the two points. Potential difference equal to work divided amount of charge equal 44,000 / equal volt. Problem number four. Decreate the quantity of electricity that flow in wire when an electric current of intensity 15 ampere. buses for 6 minutes through these wires or conductor. Quantity of electricity equal current intensity times time equal 15 amp time 6 minute time 60 to convert it into seconds equal 5,400 column. Problem number five. Calculate the current intensity that passes through conductor of resistance 22,000 ohm for 2 minutes. If the potential difference between its terminals equals 220 volt, LR resistance equal potential difference will be divided current intensity. So, current intensity equal potential difference divided LR electric resistance. equ= LB / equal 220 volt divided 202,000 ohm equal 0.01 01 ampere. Problem number six. quantity of charge 360 column bus in bus in conductor through time of 1 hour. Find the electric potential difference for the electric source if the resistance of the conductor is 2,200 ohm. Current intensity equal amount or quantity of charge divided time equal 360 column divided 1 hour * 60 * 60 to convert into second equal 0.1 ampere potential difference equal distance* current intensity equal 2,200 ohm * 0.1 ampere equal 220 volt. Problem number seven. If the potential difference between the two pools of device equal to 140 volts, what is the electric resistance of the phone wires if the current intensity is 30 ampere. Air resistance or electric resistance are equal potential difference divided current intensity equ= 240 divided equal 8 ohm in this unit or this lessons contains these concepts. Number one, radio activity. Number two, the electric resistance, current intensity, and the potential difference. Number three, the methods of connecting the cells in electric circuits like serious connection and par connection.