Changes Around Us

Q. The requirement of a fuse is that it must be a/an:

1. 
   insulator with low melting point
   
2. conductor with low melting point
   
3. insulator with high melting point
   
4. conductor with high melting point

Q. Litmus is a indicator obtained from .

1. natural
2. lichens
3. mosses
4. synthetic

Q.

By what common name are the substances on the left of the arrow $(\to )$ in a chemical equation called?

Q. Express $200+30+5+\frac{4}{100}+\frac{7}{1000}$
as a decimal number and find its hundredths digit.

1. 235.47, 7
2. 235.047, 4
3. 235.47, 4
4. 234.057, 7

Q. If the time period of a simple pendulum is 4 seconds. How much time (seconds) would it take to complete 24 oscillations for the pendulum?

1. 72
2. 48
3. 96
4. 24

Q.

Which of the following is an example of a producer?

1. Sun

2. Fern

3. Chestnut

4. Ant

Q. A lamp post made of which amongst the following materials will rust easily?

1. Galvanised iron
2. Stainless steel
3. Iron
4. Painted steel

Q. Deepak can paint $\frac{3}{5}$ of a house in one day. If he continues working at this rate, how many days will he take to paint the whole house?

1. $\frac{5}{3}$
2. $\frac{5}{2}$
3. 5
4. 3

Q.

4. Give two examples where burning of a substance is an undesirable change.

Q.

What is the male part of a flower?

Q.

Classify the following into physical and chemical change.

Magnetization of an iron piece

Q. Pick the odd one out.

1. Turmeric
2. China rose
3. Litmus
4. Methyl orange

Q. $\left(\frac{1}{3}\right)$ divided by $\left(\frac{3}{5}\right)$ is ____.

1. $\frac{1}{3}$
2. $\frac{1}{5}$
3. $\frac{5}{9}$
4. $\frac{9}{5}$

Q. Rusting of iron can be identified by change in it's:

1. shape
2. volume
3. colour
4. state

Q. I had $\frac{1}{5}$ of a pizza and now I want to divide the rest equally into 4 parts. Each part will be of how much and it's corresponding reciprocal will be respectively?

1. 5, $\frac{1}{5}$
2. $\frac{1}{5}$, 5
3. $\frac{4}{5}$, 4
4. $\frac{4}{5}$, 5

Q.

Statement B: Cooling can also bring about change.

Select the correct option about the given statements.

1. Group B

2. Both A and B are correct.

3. None of them are correct.

4. Group A

Q. When you put a metal key into its metal lock, you find the key is too tight. Which of the following methods will you adopt to make the key fit properly?
(a) Heat the key and the lock.
(b) Cool the key and heat the lock.
(c) Heat the key and cool the lock.
(d) Cool the key and the lock.

Q. Razia conducted an experiment related to percolation rate. It took 40 min for 200 mL of water to percolate through the soil sample. Calculate the rate of percolation. [2 marks]

Q.

Differentiate between physical and chemical changes.

Q. $\frac{11}{7}+\frac{9}{7}=?$

1. $\frac{17}{7}$
2. $\frac{18}{7}$
3. $\frac{20}{14}$
4. $\frac{20}{7}$

Q.

The length of the Pendulum of $2$ seconds time period is

1. $200cm$

2. $50cm$

3. $75cm$

4. $100cm$

Q. <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Classify the following as natural or synthetic indicators.
Turmeric, red cabbage, phenolphthalein, methyl orange, litmus paper.

Q. Which of the following options is correct about an improper fraction?

1. Numerator > Denominator
2. Numerator < Denominator
3. Denominator = $0$
4. Numerator = $0$

Q. Curdling of milk cannot be reversed.

1. False
2. True

Q. Rusting of iron can be identified by change in it's:

1. volume
2. colour
3. state
4. shape

Q. A torn paper cannot be brought back to its original state.

1. True
2. False

Q. Pair the given images with their respective phenomena.

1. 
2. 
3. 
4. Boiling
5. Melting
6. Condensation

Q.

The fuse has a special wire, the melting point of which is __________ than the metals which are used to make conducting wires.

Q.

Explain the differences between physical and chemical change.

Q. What is hysteresis and flux leakage?