Question

1. Given below are the pH values of different liquids 7.0,14.0 4.0 and 2.0 which of these could be that of

a) Lemon juice

b)  Distilled water  

c) Sodium hydroxide solution  

d)  Tomato juice


2. Draw a circuit diagram having the following components

a) Bulb

b) two cell battery.    

c)  Ammeter  

d)  closed Key

3. An electric iron of resistance 25 ohms takes a current of 5 amperes. calculate the heat developed in 60 seconds

4. What is the role of fuse used in series with any electrical appliance? why     should a fuse with defined rating not be replaced by one with a larger rating?

5. a) A milkman adds a very small amount of baking soda to fresh milk.

          Why does he shift the pH of the fresh milk from 6 to slightly alkaline?

e) mention pH range within which our body works.

f)  Explain how antacids give relief from acidity.

g) Mention the nature of toothpastes. How do they prevent tooth decay?

​

Answer 1

Answer:

3) The amount of heat (H) produced is given by the joule’s law of heating as H= Vlt

Where,

Current, I = 5 A

Time, t = 30 s

Voltage, V = Current x Resistance = 5 x 20 = 100V

H= 100 x 5 x 30 = 1.5 x 104 J.

Therefore, the amount of heat developed in the electric iron is 1.5 x 104 J.

4) Fuse is used for protecting appliances due to short circuiting or overloading. ... If a fuse is replaced by one with larger ratings, the appliances may get damaged while the protecting fuse does not burn off. This practice of using fuse of improper rating should always be avoided.

Explanation:

I I only explain answer of 3 and 4

hope it's helped you please follow me and like me

..