A body measures 25 m. State the unit and the magnitude of unit in the statement. Maximum students of CISCE Class 9 prefer Selina Textbook Solutions to score more in exam. Because such scales are impractical and pose difficulty in plotting intermediate points. How can this accuracy be increased? While measuring the radius of a sphere, the main scale reading is 2.90 cm and the 5th vernier scale division coincides with main scale. The thimble of a screw gauge has 50 divisions for one rotation. Name two factors on which the time period of a simple pendulum does not depend. Example. Define the terms : time period as related to a simple pendulum. Find the ratio of their lengths. (b) Amongst the various physical measurements recorded in an experiment, which physical measurement determines the degree of accuracy? He measures it to be 1.4 mm. Answer: Answer: We know that time period of a simple pendulum is independent of its mass. (a) What do you understand by the term graph? 2. why we need measurements 3. measurements in experimentation 4. typical collections of measurements 5. mathematics of measurement 6. instruments for making measurements 7. experiment with weighing machines 8. selection of items for measurement 9. measurement of thread strength epilogue selected readings glossary index 6 8 15 23 41 56 80 96 (c) Candela (a) mass of bob Length of second’s pendulum is 100 cm. (c) Metre length in terms of wavelength of light is considered more accurate because. If the actual boiling point of water is 99.4°C, calculate the percentage error. Absolute error = B.P.2 – B.P1 = 99.4 – 97.8 = 1.6°C, Question 3. The reading of main scale is known and the number of vernier scale divisions coinciding with main scale are known. or one metre is defined as the distance travelled by the light in 1/299,792,458 of a second in air/vacuum. (v) Second : “A second is defined as 1/86400 th part of a mean solar day.” Give three examples. Question 6. (a) Foot (Ft) Calculate the least count and the diameter of a wire. Answer: Acceleration due to gravity on the surface of moon. Draw a graph of l, the length of simple pendulum against T2, the square of its time period. Now solid body is tied with a cork and then immersed in water so that the water level rises to 40 ml. What is a simple pendulum? Which of the following do not affect the time period of a simple pendulum? Answer: What is the need for measuring length with vernier callipers? Express the number in terms of significant places when, Answer: Compare the time periods of the two pendulums of lengths 1 m and 9 m. A pendulum completes 2 oscillations in 5 s. What is its time period? The wavelength of light does not change with time, temperature, pressure etc. (b) A best fit line shows that two variable quantities are directly proportional to each other. (b) Frequency: “It is the number of vibrations or oscillations made in one second.”It is denoted by f or n and its unit is Hertz (Hz) or per second (s-1). is 0.01 cm If the number of divisions on main scale is 10 to a centimetre and circular scale has 100 divisions, calculate. It is difficult to write or remember them. (b) millimetre ... ICSE 9 Physics ... Get the revision notes in your mailbox! It is not necessary that graph line should pass through all points. State three uses of the vernier callipers. Level of water in measuring cylinder when a solid body is immersed in it V2 = 37 ml Question 6. How does a graph help in determining the proportional relationship between two quantities? The least count of a vernier callipers is 0.0025 cm and it has an error of + 0.0125 cm. Find its (a) Frequency and (b) Time period. Get the revision notes in your mailbox! (b) Name the devices commonly used to measure 100 divisions in 1 m). Answer: If actual velocity of sound is 332 ms-1, calculate the percentage error. If observed diameter is 0.557 cm, then : The level of water in a measuring cylinder is 12.5 ml. There also exists natural experimental studies. What do you mean by zero error of a screw gauge? Physical quantity = Magnitude × Unit. (b) Constant of proportionality : can be determined from the best fit straight line by calculating the slope of graph by using the formula. What is the reason for your answer? (b) We know time period of a simple pendulum is inversely proportional to the square root of acceleration due to gravity. What would be the ratio of their time periods? Main scale divisions of vernier callipers in one centimetre = 20 Unit. (a) What do you understand by the term order of magnitude of a quantity? (a) Define mass. Answer: A seconds pendulum is taken to a place where acceleration due to the gravity falls to one-fourth. Selina Concise Mathematics Class 8 ICSE Solutions Chapter 20 Area of Trapezium and a Polygon Selina Publishers Concise Mathematics Class 8 ICSE Solutions Chapter 20 Area of Trapezium and a Polygon Area of Trapezium and a Polygon Exercise 20A – Selina Concise Mathematics Class 8 ICSE Solutions Question 1. Question 1. (a) Degree of accuracy : It means that we can measure a quantity, without any error of estimation. Precautions for plotting points on a graph : Question 4. Answer: Question 2. Answer: Question 2. (c) When positive error is 7 divisions and L.C. Question 1. Answer: Selina Publishers Concise Physics for Class 9 ICSE Solutions all questions are solved and explained by expert teachers as per ICSE board guidelines. Thus the error in 72.5 is +0.05. List Your Institute, Event, Course, Service, You have already subscribed to 2 schools. (d) Kilometre (km). 2. How do you determine it? Question 3. Selina textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students. It is denoted by ‘a’. Support your answer by an example. If the micrometer has 10 divisions to a centimetre on main scale and 100 divisions on circular scale, calculate, Question 2. 3. Exe-1 Measurements and Experimentation Class-9 Goyal Brothers ICSE Physics Solutions Ch-1. Express the distance in metre . The skin is the largest organ of the body, with a total area of about 2 square metres. Question 5. The time periods of two pendulums are 1.44 s and 0.36 s respectively. Least count (L.C.) = 0. Goyal Brothers Measurements and Experimentation Class-9. ... ICSE 9th CLASS Science OTHER CHAPTERS. (c) Micrometre (µm) (a) Time period (T) : “is the time taken to complete one oscillation.” Its unit is second (s) and time period is denoted by ‘T” Answer: = – Coinciding division of C.S. Download Formulae Handbook For ICSE Class 9 and 10. Explain the terms : Pitch . Question 1. (b) If the vernier has a negative error of 0.04 cm, calculate the corrected radius of sphere. One metre is defined as 1,553,164.1 times the wavelength of the red line in emission spectrum of cadmium. What would be the ratio of their time periods? Take a measuring cylinder and fill water up to certain level. Systems of unit and units in S.I system, 3. Question 3. If the length of a simple pendulum is made one-fourth, then its time period becomes. (b) Positive zero error This standard is called a unit Distance moved by spindle (screw) = 2.5 mm When the flattened end of the screw comes in contact with stud, ratchet becomes free and makes a rattling noise. A solid body is immersed in it so that the level of water rises to 37 ml. Which part of vernier callipers is used to measure. No. S.I. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a particular factor is manipulated. (a) What is a second’s pendulum? Physics, like other branches of science requires experimental study which involves measurement. unit of area is obtained by multiplying the fundamental unit ‘m’ with itself. Figure shows a screw gauge in which circular scale has 200 divisions. of circular scale division = 100 Describe the procedure to measure the diameter of a wire with the help of a screw gauge. When the screw gauge is used to measure the diameter of wire the reading on sleeve is found to be 0.5 mm and reading on thimble is found 27 divisions.