Question

Please answer the 19 ,22 and 23 questions...

Answer 1

Questions

Q 1) You are given four elements with some description of each element. Place them in the modern periodic table (state which period and group they belong)

1. Essential for breathing and burning.
2. Inactive, two electrons in the outermost shell
3. Atom has same number of electron, proton and neutron and is used in fertilizer industry
4. This element forms the hardest naturally occurring substance as allotropes.

Q 2) Observe the following ray diagram of an object where the image A'B' is formed after refraction from a convex lens. On the basis of the above information, answer the questions

1. the position of the object AB
2. Siz of the object would be ____ than the size of the image.

Q 3) Draw a circuit diagram of an electric circuit containing a cell, a key, a resistor of 4 ohm in series with a combination of two resistors (8 ohm each) in parallel and a voltmeter across parallel combination. Each of them dissipate maximum energy and can withstand maximum power of 16 W without melting. Find the maximum current that can flow through the resistors.

$\rule{200}2$

Answers

1)

1. The element is clearly Oxygen. Electronic configuration of oxygen = 2, 6. Hence, oxygen belongs to the second period and group 16
2. The element is Helium. It is found in the first period, group 18 (noble gas)
3. The element is Nitrogen. Electronic configuration of nitrogen = 2, 5. Hence, nitrogen belongs to the second period, group 15
4. The element is carbon. It has electronic configuration = 2,4. Hence, belonging to the second period and group 14.

$\rule{50}3$

2) Since the image is formed between $\sf F_2$ and $\sf 2F_2$, the object lies beyond $\sf 2F_1$. Position of object → Beyond $\sf 2F_1$

The image formed in the case is diminished, hence the size of the object would be larger than the size of the image.

$\rule{50}3$

3) Refer attachment for circuit diagram.

We know that, P = I²R

4 ohm resistor draws a power of 16 W

→ 16 = I²(4)

→ I² = 4

→ I = 2 A

Also, equivalent resistance of parallel circuit = 4 ohm.

→ 4 ohm resistor is in series with parallel combination of 8 ohm

→ 4 ohm resistor is in series with another resistor of 4 ohm

→ Current will be same in the two combination

Now, the current of 2 A will be distributed equally in the parallel combination (because both resistors are equal)

→ the current going in 8 ohm resistor would be 1 A

Maximum current drawn by 4 ohm resistor = 2 A

Maximum current drawn by 8 ohm resistors = 1 A