Exams

Here in the given numbers 91 is a Composite number. Since it has factors of 7 and 13 other than 1 and itself.

Composite Numbers :

A composite number is a positive integer which is not prime (i.e., which has factors other than 1 and itself).

Examples :: 4, 6, 8, 12, 14, 15, 18, 20, ...

The surface area of a cube = 6a2 =  6 side2

New  Surface area = 6 x 1.44a2

Therefore, 0.44a2a2x100 = 44%

0.127 expressed as a fraction = 127/1000

1/8 can also be expressed as (1 x 125) / (8 x 125) = 125/1000

The difference is 2/1000, which is 1/500

The kidneys deactivate vitamin D and stimulate the activity of osteoclasts is wrong among the functions of kidneys.

The kidneys are two bean-shaped organs in the renal system. They help the body pass waste as urine. They also help filter blood before sending it back to the heart.

The kidneys perform many crucial functions, including:

• maintaining overall fluid balance.
• regulating and filtering minerals from the blood.
• filtering waste materials from food, medications, and toxic substances.
• creating hormones that help produce red blood cells, promote bone health, and regulate blood pressure.

Let the number of students in the class be 'x'.
Given if 1 is absent rest of people can be divided into 6 equal parts i.e (x-1)/6.........(1)
And given if 2 are absent rest of people can be divided into 7 equal parts i.e (x-2)/7.....(2)
From (1)&(2), we get
x-1/6 = ((x-2)/7) + 1
=> x = 37.

Copper Iodide is the systematic name of the given compound (CuI)s.

An electrically charged atom or group of atoms formed by the loss or gain of one or more electrons is called an Ion.

Cation:

An ion is a cation (positive ion) if it is created by electron loss and is attracted to the cathode in electrolysis.

Anion:

An ion is an anion (negative ion) if it is created by an electron gain and is attracted to the anode.

The valence of an ion is equal to the number of electrons lost or gained and is indicated by a plus sign for cations and a minus sign for anions.

Ex: Na +, Cl−, Ca ++,...