ECAT Pre General Science MCQ Test With Answer for Mathematics Chapter 1

If in a set of real no a is additive identity then

• a+a = 2a A
• a+a = 1 B
• a+a = 0 C
• None of these D

if Z1 = 1+i, Z2= 2+3i, then |Z2 -Z1| =

• √3 i A
• √7 B
• -2-i C
• √5 D

√23 is

• A rational number A
• A irrational number B
• An even integer C
• A factor of 36 D

If z = (x,y) , then  z ̅  =

• (-x,y) A
• (x,-y) B
• (-x, -y) C
• None of these D

• z is purely imaginary A
• a is any complex number B
• z is real C
• None of these D

• x A
• 
  B
• y C
• 
  D

a.a^-1 = a^-1.a = 1 is a

• Commutative law of multiplication A
• Multiplicative identity B
• Associative law of multiplication C
• Multiplicative inverse D

The multiplicative inverse of 2/3 is

• 3/2 A
• -2/3 B
• -3/2 C
• 1 D

• 
  A
• 
  B
• 
  C
• 
  D

Gooch crucible is made of :

• Brass. A
• Porcelain. B
• Bronze. C
• Gold. D

• 
  A
• 
  B
• 
  C

• A rational number A
• A natural number B
• An irrational number C
• An integer D

Any recurring decimal represents a

• Irrational no A
• Integer B
• Rational no C
• None of these D

The square root of 2i - 20i is

• +-(5 - 2i) A
• +-(5 + 2i) B
• (5 - 2i) C
• None of these D

Every natural number is

• A prime number A
• An irrational number B
• An integer C
• An even number D

If P is a whole number greater than 1, which has only P and I are factors. Then P is called

• Wholw number A
• Prime number B
• Even number C
• Odd number D

The set {0,-1} hold closure property under

• Addition A
• Both a & c B
• Multiplication C
• None of these D

In polar form of complex number r =

• 
  A
• 
  B
• 
  C
• 
  D

• 
  A
• 1 B
• 
  C
• -1 D

• 1 A
• 3 B
• 2-i C
• -1 D

∀x,y∈ R and x < 0, y < 0, which one is true 

• xy < o A
• xy = o B
• xy > o C
• None of these D

• 0 A
• 1 B
• -1 C
• None of these D

If z₁ =√-36 ,z₂ =√-25,z3 =√-16 then

• 15 A
• 15i B
• -15i C
• -15 D

In R the number of identity element w.r.t '+' is

• One A
• Two B
• Three C
• Four D

• N A
• r B
• 2r C
• π D

Additive inverse of - a - b is

• a A
• -a + b B
• a - b C
• a + b D

• 
  A
• 
  B
• 
  C
• 
  D

• 
  
  
  A
• 
  B
• 
  C
• 
  D

• Rational A
• Irrational B
• Even C
• Odd D

• 
  A
• 
  B
• 
  C
• 
  D