**1. What is independent variable?Ans:** The independent variable is one of that variable that is changed varied or manipulated by the scientist.

**2. What is depedent variable?Ans:** Dependent variable is the response that is measured.

**3.What is control variable?Ans:** Control variable are quantities that a scientists wants to remain constant and she or he must obeserves them as carefully as the dependent variable.

**4. Give one examples of independent , dependent and control variable?Ans:** They are given below:

i)The Level of sugar in blood is dependent variable.

ii) The presence or absence of intermittent fasting is independent variable.

iii) The type of physical exercise is control variable.

**5. What is fundamental physical quantities ? Write its example.Ans:** Those physical quantites which are independent of each other are called fundamental physical quantities.

**For Example:**Length, Mass, Time and temperature etc.

**6. What is derived physical quantities? Write its example.Ans:** Those physical quantites which are derived from the fundamental physical quantities are called derived phyical quantities.

**for Example:**Volume, Density, force, work and speed etc.

**7. Why derived physical quantities dependent upon fundamental physical quantities.Ans:** Derived physical quatities dependemt upon fundamental physical quantities beacuse it is derived from the fundamental physical quantity.

**8. What is physical quantity?Ans:** The quantity which have to measured a very large number is called physical quantity.

**9. What is fundamental physical quantity?Ans:** Those physical quantity which are independence of each other are called fundamental physical quantity.

**10. What is fundamental unit? How many types are there.Ans:** Those units which are independent of each other are called fundamental unit.

**There are 7 fndamental unit they are:**

Meter | m |

Kilogram | kg |

Second | s |

Kelvin | k |

Ampere | A |

Candela | cd |

Mole | mol |

**11. What is derived Unit?Ans:** Those unit which are formed by the combination of two or more fundamental unit are called derived unit.

**12.Some Physical quantity which is given below:a.Densityb.Forcec.workd.powere.pressure**

**a.Density**

solution,

we know that,

$mass\left(m\right)=kg$

$volume\left(v\right)=m\times m\times m$

then,$Density\left(D\right)=\frac{mass}{volume}=kg/{m}^{3}$

**b.Force**

solution,

we know that,

$\mathrm{F}=\mathrm{mass}\times \mathrm{accleration}$

$=\mathrm{kg}\times \frac{\mathrm{m}}{\mathrm{s}\times \mathrm{s}}$

$=\mathrm{kgm}/{\mathrm{s}}^{2}$

**c.Work**

solution,

we know that,

$\mathrm{Work}=\mathrm{F}\times \mathrm{d}$

$=\frac{\mathrm{kg}\times \mathrm{m}\times \mathrm{m}}{\mathrm{s}\times \mathrm{s}\times \mathrm{s}}$

$=\mathrm{kg}{\mathrm{m}}^{2}/{\mathrm{s}}^{3}$

**d.power**

solution,

we know that,

$\mathrm{Power}\left(\mathrm{p}\right)=\frac{\mathrm{work}\mathrm{done}\left(\mathrm{w}\right)}{\mathrm{time}\left(\mathrm{t}\right)}$

$=\frac{\mathrm{F}\times \mathrm{S}}{\mathrm{t}}[\because \mathrm{w}=\mathrm{F}\times \mathrm{S}]$

$=\frac{\mathrm{m}\times \mathrm{a}\times \mathrm{s}}{\mathrm{t}}$

$=\frac{\mathrm{kg}\times \mathrm{m}\times \mathrm{m}}{\mathrm{s}\times \mathrm{s}\times \mathrm{s}}$

$=\mathrm{kg}{\mathrm{m}}^{2}/{\mathrm{s}}^{3}$

**e.pressure(p)**

solution,

we know that,

$\mathrm{pressure}\left(\mathrm{p}\right)=\frac{\mathrm{Force}}{\mathrm{Area}}$

$=\frac{\mathrm{kg}\times \mathrm{m}}{{\mathrm{s}}^{2}\times {\mathrm{m}}^{2}}$

$=\frac{\mathrm{kg}}{{\mathrm{ms}}^{2}}$

$=\mathrm{kg}/{\mathrm{ms}}^{2}$

**13. The unit of pressure is derived unit?justify.Ans:**Derived unit means those units which is formed by the combination of two or more unit.According to this pressure is also formed by combination of force and Area which is

**pressure(P) =( Force / Area)**.

*Hence, it is formed by the combination of two or more than two units so it is derived unit.***14. The unit of accleration is derived unit?justify.Ans: **We know that derived uit means those unot which is formed by the combination of two or more fundamental units. According to this accleration is also formed by

**Accleration(a) = (Change in velocity / time taken)**

= m/s

= m/s

^{2}

*Hence, it is formed by the combination of two or more than two units so it is derived unit.***15. What is Variable?Ans:** Variable are the factors, traits and conditions that can be modified and measured.

**16. What are two features of variables?Ans:** The two features of variable are:

i) It is easy in scientific learning.

ii) It is used in scientific method.

**17. Name any three types of variables.Ans: **The three types of variable are given below:

i) Dependent Variable

ii) Independent Variable

iii) Controlled Variable

**19. What are independent and dependent variable?Ans: **The independent variable is the one that is changed varied or manipulated by scientist.

Dependent variable is the response that is measured.

**20. What is controlled Variable?Ans:** Anything that is held constant or limited in research study is called controlled variable.

**21. Define unit with any two examples.Ans:** The symbols that denoted the amount of any quantities is called unit.

Examples: i). Length (m)

ii). acceleration (m/s

^{2})

**22. What are fundamental units? Give any two examples.Ans: **The units which are independent upon other unit is called fundamental units.

**Examples:**i. Length (m)

ii. Time (s)

**23. Write down SI unit of the following physical quantity.Ans:** They are given below:

Temperature | Kelvin (k) |

Mass | Kilogram (kg) |

Velocity | (m/s) |

Force | (kgm/s^{2}) |

Pressure | (kg/ms^{2}) |

**24. Write down the concerned physical quantities of the following units.Ans:** They are given below:

Nm | Work |

Pa | Pressure |

m/s | Speed/velocity |

M^{3} | Volume |

N | Force |

m/s^{2} | Acceleration |

Hz | Frequency |

**25. Differentiate Between **

Independent | Dependent |

The independent variable is the one that is changed, varied or manipulated by scientist. | The dependent variable is the response that is measured |

In growing plant experiment different types of soil are independent variable. | In growing plants experiment growth of plant is dependent variable. |

**b. Dependent and Controlled**

Dependent | Controlled |

The dependent variable is the response that is measured. | Anything that is held constant or limited in research study is called controlled variable. |

In growth of plants experiment growth of plant is dependent variable. | In the plant experiment the temperature is control variable. |

**C. Fundamental Units and Dervied Units**.

Fundamental Units | Derived Units |

Fundamental units are those unit which are independent of other unit of physical quantity. | Derived units are those units which are depended on other units of physical quantity. |

For example: meter,kilogram etc | For example:m/s, N etc |

**26. What is mean by a controlled variable? Write with example.****Ans:** Anything that is held constant or limited in a research study is called a control variable.

for example: In plant experiment, the temperature is a control variable.

**27. Why is the unit of length called a fundamental unit?****Ans:** The unit of length called a fundamental unit beacuse the unit of length independent of each other.

**28. Why is the unit of pressure called a derived unit?Ans:** The unit of pressure called a derived unit because the unit of pressure is formed by the combination of two or more fundamenal unit.

**29. Meter and Second are called fundamental units.Why?****Ans:** Meter and second are called fundamental unit beacuse it is independent of each other.

**30. Watt and Joule are callled derived units.Why?Ans:** Watt and joule are called derived units beacuse it is formed by the multiplication or division of two or more fundamental units.

**31. Variable are very important in scientific study.Why?****Ans:** Variables are very important in scientific study because it makes scientific study and understand.

**32. Samip wanted to know the effect of increasing temperature on the solubility of copper sulphurs. Write down the independent, dependent and controlled variable in this research questions.Ans:** They are:

Independent Variable.

– Water are independent variable.

Dependent Variable.

– Copper Sulphate dependent variable.

Controlled Variable.

– Temperature is the control Variable.

**33. Analyze the units involved in the following equations.**

**i).$V=u+at$ solution;The above equation can be checked by analysing units involved in equationi.$V=u+at$unit:$\frac{m}{s}=\frac{m}{s}+\frac{m}{{s}^{2}}\times s$or,$\frac{m}{s}=\frac{m}{s}+\frac{m}{s}$While analysing the units of formula,v= u+at we ge,$\frac{m}{s}=\frac{m}{s}+\frac{m}{s}$So, the above equation is homogeneous and vaild. ii).$s=u+\frac{1}{2}a{t}^{2}$ solutionThe above equation can be checked by analysing the units involved in equation$s=u+\frac{1}{2}a{t}^{2}$unit:$m=\frac{m}{s}\times s+\frac{1}{2}\frac{m}{{s}^{2}}\times {s}^{2}$$or,m=m+\frac{1}{2}m$While analyzing unit formula, $s=u+\frac{1}{2}a{t}^{2}$ we get,$m=m+\frac{1}{2}m$so, the above equation is homogenous and vaild. iii). ${v}^{2}={u}^{2}+2as$solution,The above equation can be checked by analyzing the unit involved in equation.$formula:{v}^{2}={u}^{2}+2as$$units:\frac{{m}^{2}}{{s}^{2}}=\frac{{m}^{2}}{{s}^{2}}+2\frac{m}{{s}^{2}}\times m$$or,\frac{{m}^{2}}{{s}^{2}}=\frac{{m}^{2}}{{s}^{2}}+\frac{2{m}^{2}}{{s}^{2}}$while analyzing the formula ${v}^{2}={u}^{2}+2as$we get,$\frac{{m}^{2}}{{s}^{2}}=\frac{{m}^{2}}{{s}^{2}}+\frac{2{m}^{2}}{{s}^{2}}$So, the above equation is homogenous and valid.**

**34. Write down the significance of the variables in scientific learning.Ans:** The significance of the variables in scientific learning are given below:

i) Variables are very important in research to see variables define them and control or measure them.

ii) They are important to understand.

iii) They are the basic units of the information studied and interpreted in research study.

iv) Variable helps to measure concepts in a study.

**35. Soni wanted to observe the growth of plants in different types of soil. Identify three types of variables in her experiment.Ans:**

**36. Write down the things to be remembered regarding variables.Ans:** They are given below:

i) There should be oly one independent in an experiment or a research work.

ii) The variable except independent variable and dependet variable should be controlled.

iii) While presenting the relation between two variables in a graph dependent variable should be plotted on y-axis and independent variable is plotted on x- axis due to this dependent variable is called horizantal variables.

**37. Identify independent, dependent and controlled variable is the following experiment/research questions.Ans: i) Effects of amount of water on growth of plants. **

ans: Independent Variables

**ii) Effects of size of recatants on rate of a chemical reaction.**

ans: Control variables

**iii) Effects of a size temperature on growth of plants.**

ans: Control variables

**38. Explain the variable in scientific learning.Ans:** They are given below:

i) It is very important in research to see varibales define them and control and measure them.

ii) They are important to understand.

iii) The basic units of the information studied and interpreted in research studies.

iv) Variable help to measure concept in a study.