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Multiply the binomials: (2pq + 3q²) and (3pq – 2q²)

Answer: 6p2q2 + 5pq3 - 6q4 Polynomials are algebraic expressions that consist of variables and coefficients. Polynomials are of 3 different... View Article

Multiply the binomials: (2x + 5) and (4x – 3)

Answer: 8x² + 14x - 15 Polynomials are algebraic expressions that consist of variables and coefficients. Polynomials are of 3 different types... View Article

Multiply the binomials: (3/4 a² + 3b²) and 4( a² – 2/3 b²)

Answer: 3a4 + 10a²b² - 8b4 Polynomials are algebraic expressions that consist of variables and coefficients. Polynomials are of 3... View Article

Multiply the binomials: (a + 3b) and (x + 5)

Answer: ax + 5a + 3bx + 15b Polynomials are algebraic expressions that consist of variables and coefficients. Polynomials are of 3 different... View Article

Multiply the binomials: (y – 8) and (3y – 4)

Answer: 3y2 - 28y + 32 Polynomials are algebraic expressions that consist of variables and coefficients. Polynomials are of 3 different types... View Article

Name the effect of current responsible for the glow of the bulb in an electric circuit.

Answer: Heating effect of electric current responsible for the glow of the bulb in an electric circuit. Electric current's heating impact is... View Article

Name the part of the eye which gives colour to the eyes

Answer: Iris the part of the eye which gives colour to the eyes. The eye is an important and one of the most complex sens organs that we humans... View Article

Name the property under multiplication used in the following. -13/17 × (-2/7) = -2/7 × (-13/17)

Answer: Commutative: It states that the order of numbers in addition and multiplication does not matter. The end result will b the same. If x and... View Article

Name the property under multiplication used in the following. -19/29 × 29/-19 = 1

Answer: The multiplicative inverse of a number N is represented by 1/N or N-1. It is also called reciprocal, derived from the Latin word... View Article

Name the property under multiplication used in the following. -4/5 × 1 = 1 × (-4/5) = -4/5

Answer: The multiplicative inverse of a number N is represented by 1/N or N-1. It is also called reciprocal, derived from the Latin word... View Article

Name the scale on which the destructive energy of an earthquake is measured. An earthquake measures 3 on this scale. Would it be recorded by a seismograph? Is it likely to cause much damage?

Answer: Richter scale is used to measure the destructive energy of an earthquake. The scale has a reading from 1 to 10. The Richter scale is a... View Article

Name three liquids, which when tested in the manner shown in Fig., may cause the magnetic needle to deflect.

Answer: Saltwater Lemon juice Vegetable oil Any liquid solution containing acidic or basic salt will cause this effect. A solution ionises and... View Article

Name two musical instruments which produce sound by vibrating strings?

Answer: Guitar and sitar are two musical instruments with vibrating strings that make sound. The vibrating part in a sitar are stretched... View Article

Near the earth’s surface air rises up whereas _ air comes down.

Answer: Near the earth’s surface, warm air rises up whereas cold air comes down. The movement of air is mainly caused by the differences... View Article

Observe Fig. Which of these two circuits A or B shows the correct observation?

Answer: Because a greenish blue spot is always created around the positive terminal of the battery, Circuit A indicates the correct observation.... View Article

Observe the circuit given in Fig. Boojho set up this circuit for purification of copper. What will be the nature of – (i) plate A (ii) plate B (iii) the solution? Explain the process of purification.

Answer: (i) In plate A- Pure copper (ii) In plate B- Impure copper (iii) The solution – Copper sulphate solution Electroplating is the... View Article

Observe the following circuit given in Fig. Current does not flow in the circuit if there is a gap between the two wires. Does it indicate that air is a poor conductor of electricity? Does air never conduct electricity? Explain.

Answer: Air is a poor conductor of electricity in general. However, under some conditions, such as when lightning strikes, air conducts... View Article

Observe the following circuits carefully. In which circuit will the bulb glow. Write ‘Yes’ or ‘No’ in the blank space provided along each of the circuit given in Fig.

Answer: No Yes. Because iron is a metal, it is an excellent conductor of electricity. No. Eraser is material which does not a conductor of... View Article

Observe the vessels A, B, C and D shown in Fig. carefully. The volume of water taken in each vessel is as shown. Arrange them in the order of decreasing pressure at the base of each vessel. Explain.

Answer: The pressure at depth due to the liquid column is determined by the Gravitational acceleration (g) The density of the liquid The liquid... View Article

Obtain the product of (i) 2, 4y, 8y² , 16y³ (ii) a, 2b, 3c, 6abc (iii) m, -mn, mnp

Answer: 2 × 4y × 8y2 × 16y3 ⇒ (2 × 4 × 8 × 16) × (y × y2 × y3) We know that, We... View Article

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